My first scenes

I am not new to blender, I have had a copy since 1. something, and have been messing around with it, but never really created anything here are my first three attempts.
I would apreciate advice.
http://www.putfile.com/pic.php?img=4180690
http://www.putfile.com/pic.php?img=4180690
http://www.putfile.com/pic.php?img=4180687

Detail, detail, detail! I would say that these are all good (the lawn mower is the best), however detail is something you are lacking. I would try applying some textures to the tree and the roof of the house. You’re on the right track, that’s for sure, but I do think that the newest version of blender and a few good tutorials will have you (and myself for that matter since I’m new) blending like a pro! Blend it up!

I just made those on the new one, How do you apply diffrent color paint/textures to diffrent sections of objects in the new version?