First, forget perfection. There is none. As someone who has judged for many years, I can say I've yet to see the perfect model. Some come really close and I've seen some master figure painters who are on the razor's edge of perfection, but I'm still waiting to see it.
Second, not starting will absolutely, positively never lead to quality builds. Accept that your first efforts will not measure up to people who've been doing htis for years. You need to learn a new skill set and the only way to do that is to do it. "Do or do not... there is no try," as Yoda said.
Third, start simple, go for out of box builds. Become proficient at filling seams, aligning parts correctly, laying down paint properly, applpying decals straight and without silvering, etc. These are the basic skills upon which to build. Don't buy anything after market until you can do a decent build OOB. Don't weather until you are happy with a clean model.
You can't expect to qualify for, let alone win, the Boston Marathon the first time you lace up your running shoes. Likewise, you shouldn't expect your first build to be a cover for FSM.