Pick a night shot:

1.copy and paste the fireworks image into your night shot
2.blend layers" lighten"
3.revise curves so the base night colour of the image blends into the original image.Ideally you want this layer behind the building,so manipulate the layers accordingly.

Keep it simple.

Faking Caustics is easy.I have attached an image,many of which you can download from the internet.This job was a rush job,I wasnt able to wait for vray to render with caustics,so I cheated.

All that is required is copying the caustic image,distorting to align with the ceiling and deleting where it does not need to be.You could also copy the caustic image to the pool surface and add a small gaussian blur to help.

You could also copy the caustic image to the wall,distort and add a layer mask downwards to suggest the reflection is fading away.
Keeping it simple.

1.Locate an image of foreground trees - if image is coloured - colour desatutrate
2.increase curves- (alters black and white values)
3.copy and paste
4.remove areas not needed
5.blend layer with "multiply"

Its simple.

OK,here are 2 more tips,still in the winter theme.The first is making plants look icy/frosty.

FROST COVERED PLANTS:
1.open green plant and duplicate layer
2.desaturate the copied layer
3.Increase curves(see seting on jpg attached).This results in an almost white image.
4.selectively erase the copied white image from the bottom up.

BLENDING LARGE AREAS OF FOREGROUND:
The first image shows a screensnap of a recent project.What is missing is the main snow foreground.
1.Find a source image with the correct/similar lighting.
2.select the part you want -but use a feathering of 20-25 in the selection so the edges are blurred.You can see in the middle image that there are elements projecting up but these can easily be hidden with vegetation.Then start copying the layer around,again selectively erasing.
The main thing to understand with adding large areas of foreground is to feather/blur the edges.It isnt any more complicated than that.

I will upload a new one later showing how I add individual parts of snow,such as is on the lower wall in this image.I can promise you it wont be complicated

FROM CORNER BAR:

I have attached some low res images of renders I have completed in the last few months,but if you want to know how I do the snow,use reflection etc, then this would be the sub-forum.

This would not be a full tutorial,just a quick screensnap,short explanation, i.e copy,paste,deform,blend etc.

EXAMPLE : Reflection in a winter day - copy,paste,flip vertical and motion blur at 90 degrees,40 strength.Ideally,it wouldnt get any more complicated than this.Maybe its a "Tips and Tricks".Anybody can upload,just keep it simple

Sorry,the last image was a low res version.Attached is a slightly different version,higher res,from a different view.These images are part of a set of images I am trying to create in my method,except that I want to be able to start an image and finish in 15 minutes,not including the render.

I have created a library of entourage for NPR images over the last couple of years.Photor-ealistic imagery for the end result is easy enough,but NPR is where,as a starting point,mood can be created.

a quick exercise in creating a colourful garden based on the method I have used for previous images.I revised a lot of the original hues for green trees and was especially happy with the cherry blossom tree colour of the tree on the extreme top right.So much so that I think I will attempt a full cherry blossom garden next.

Adding wet grass:
1.render out an image with a reflection on the grass surface
2.locate an image for the wet grass you want to use - try and find one that has the same colour reflection as the sky in the render so it blends with the image easier.
2.distort the image so it matches the render perspective.
4.copy and paste the grass layer over the original rendered grass.
5.using a soft eraser ,remove the grass that overflows onto the road.(material ID can be of great use here)
Use the clone tool if required to smooth out any transitions.
6.edit the curves of the new grass layer.this step is optional.

The second image shows another before and after image

attached is a very quick step by step to show how I create autumn trees.I used this technique to in this image recently uploaded to the gallery:
http://forums.sketchucation.com/viewtopic.php?f=81&t=41500
1.Start with a green tree
2.duplicate the layer and change the hue colour to a more red/brown colour
3.start selectively erasing the top red layer using a soft edged eraser.The reason its soft edge is to ensure the colours blend into each other.You could just change the green tree to red but Autumn trees normally have different shades of colour within each individual tree,so this helps give the effect of different parts of the leaves changing colour.
4.merge the 2 layers.
5.copy and repeat to create a line of trees.I have used the same tree for this step by step but normally I would use different types to create more variation.Dont be afraid to mix strong colours side by side as that is eactly what happens in real life autumn trees.

a variation with the same stream as in the third image uploaded in this set on page 1.All that was changed is the water/ice colour has been colour-toned to match the sky.

An old model,previously uploaded.This time its an autumn view,using the same technique that I explained in this small step by step:http://forums.sketchucation.com/viewtopic.php?f=179&t=41337
i.e overlaying foreground elements with feathered edges so they blend together better.The building is still the same original render as before but with different photoshoped surroundings.To assemble this image took about 30 minutes.

Ive just noticed that there is now a special post-processing forum- Thanks Rich!(can the few step by steps I've uploaded to the corner bar be transferred across to this new forum?)

This is how I add snow to walls buildings etc.:
1.select a piece of snow that matches your image
2.select the outline and copy
3.paste - then distort,scale to fit the scene
4.add a layer mask- use a gradient light to dark from top downwards-this will help melt the snow onto the wall.depending on which way the sun is shining,you can add additional layer masks to show the snow melting in the light,and more solid in the shade.

As I said,this is not complicated,
but I would also add,surely there is someone else out there that has some other post-processing ideas.

First things first,from my point of view,and I know this is not what was asked,I think the composition is perfect.Its an example of how to show a building.Its not just plonked down on a horizon line with something to the left and something to the right.Its a brilliant example of placing a building in its environment.
From the images,I would go for the second option but with the texture from the road in the first.After that,it works amazingly well.

OK,here are 2 more tips,still in the winter theme.The first is making plants look icy/frosty.

FROST COVERED PLANTS:
1.open green plant and duplicate layer
2.desaturate the copied layer
3.Increase curves(see seting on jpg attached).This results in an almost white image.
4.selectively erase the copied white image from the bottom up.

BLENDING LARGE AREAS OF FOREGROUND:
The first image shows a screensnap of a recent project.What is missing is the main snow foreground.
1.Find a source image with the correct/similar lighting.
2.select the part you want -but use a feathering of 20-25 in the selection so the edges are blurred.You can see in the middle image that there are elements projecting up but these can easily be hidden with vegetation.Then start copying the layer around,again selectively erasing.
The main thing to understand with adding large areas of foreground is to feather/blur the edges.It isnt any more complicated than that.

I will upload a new one later showing how I add individual parts of snow,such as is on the lower wall in this image.I can promise you it wont be complicated.

Having been a long term contributor to this website,and uploading many images,I was wondering if there any room for a unique "post-processing" sub menu on the forum.I am thinking specifically for how to deal with individual ideas,i.e how you add wet grass,reflections,foreground elements.I have been guilty in uploading images that make sense to me,but look quite complicated to others.

I have attached some low res images of renders I have completed in the last few months,but if you want to know how I do the snow,use reflection etc, then this would be the sub-forum.

This would not be a full tutorial,just a quick screensnap,short explanation, i.e copy,paste,deform,blend etc.

EXAMPLE : Reflection in a winter day - copy,paste,flip vertical and motion blur at 90 degrees,40 strength.Ideally,it wouldnt get any more complicated than this.Maybe its a "Tips and Tricks".Anybody can upload,just keep it simple.

Its pretty much about finding an image with the correct lighting for the snow.After that its a combination of cloning and distorting, copying parts around the image and blending them together.But if you dont have the correct lighting it will become very obvious very quickly.

What you need to do is find images that have the same colour sky as the sky in the render.This way,not only will you have the correct lighting,but also the correct radiosity colour on your inserted elements.

Ive overlayed some lights on the last image and just played around with the colours.Its a bit murky but i like the effect of the snow blowing in the lights.

The additional background trees are simple black and white .pngs added with a "multiply" blend,which helps to remove any white edges on the trees.The forground bushes/small trees are also hi res .pngs,inserted and scaled around the image.These were purchased from this website:
http://www.gardenhose.com/

Thanks a lot for all the positive feedback,Its always good to get.
Here Ive attached a snow storm version of this house.The colours are particularly muted and a slight blue cast added to the overall image.The falling snow was created using this technique :
http://www.youtube.com/watch?v=qWuGCA84XQk

A revised night shot.I brightened the sky and altered the snow colour so it is more in keeping with the sky colour.I also added additional foreground at the bottom as I think the original image was cropped too close to the building.