@rebeltaz said:
...And my experience would be beginner...
If you haven't already, I highly recommend watching all of the videos on this page: http://sketchup.google.com/intl/en/training/videos/new_to_gsu.html
Once you are done with them, here's another video that may help with organic modeling/cartoon characters without any plugins:
YouTube - From a little circle, grows a tree...
[flash=480,385:klski4vt]http://www.youtube.com/v/XRAL6MhoMB8?fs=1&hl=en_US[/flash:klski4vt]