Hey Yaki,
I was also facing this same issue before I joined CGcookie. What made me “panic” was the thought that everything I did had to be perfect in each and every way, and I wanted to build a bunch of small, perfect objects before building a large scene. What helped me over come this “fear” was understanding that in my final render, you couldn’t see most of the objects that I would have painstakingly put together and even if you did, it was only for a second, but you could clearly read what the object was supposed to be.
Remember – when you’re trying to render a large scene (a kitchen for exmaple) that weird bump in your coffee cup or that slightly obtuse leg on that table? No one will notice (unless they’re actively critiquing!) especially if you’re just starting out.
Set a goal to build something, no matter how large or complex or crazy. Just build it and finish it. Forgo any perfectionist qualities and just get it done, once you take a step back and see the scene come together, you’ll forget about those small imperfections!
Good luck, and I hope this helped.