Outliner is a good thing to use - make sure however to close or at least minimize it before using some of the plugins that add considerable amount of geometry to your model (like the Fur plugin or such) as SU will try update it instantly and you will get lags very easily.

As for layers, here is a good video why not to put ungrouped geometry on other than Layer 0 as in SU, layers are merely for controlling visibility and not for separating geometry.

[flash=600,470:2givdic7]http://www.youtube.com/v/fBdP499iw0Y?fs[/flash:2givdic7]

Hi Greenbelt and welcome!

Components are just simple, ordinary skp files. If you download one anywhere, you can open them or you can import them into your existing model from File > Import - where you need to select the proper file type (skp).

Or simply drag and drop it from your file list into your open SU window...

You can find the components that your component browser uses here:
C:\Program Files\Google\Google SketchUp 8\Components
They are organised into folders. You can add as many folder and into them, as many skp files as you want.