Making your own assets...

Hi, I'm a beginning game designer, and I have made only one game before. I use unity 3, sketchup 7, and blender, and I only have the free versions of all of them. So how do I make my own assets? sketchup is easy to use, but won't import any complex models. Blender imports fine, but I barely know how to use it and can't put colors on blender models. What free software can I use which will import into unity, color and all?

By "putting colors on blender models" you probably mean texturing them. You need to learn how to unwrap your 3d models and paint textures for them. Blender can do the unwrapping part, but you'll need to use a paint program like Photoshop to actually create the textures. Since you mention free, you'll probably want to look at Paint.NET, GIMP, or another free paint program instead of Photoshop.

In any case, there are plenty of tutorials online for how to model, unwrap, texture, and import models using all of the software mentioned above.