Paint! Paint like you've never paint before! Paint like your life depends on it! But seriously... paint. The nice thing about paint is that is you can paint over it - unless you've globbed on so much that you've killed and hidden the details.
For about three years, I had a Crescendo airbrush that sat in a box, collecting dust. I had built about 5 models that had no paint because I was concerned about my ability to get paint on them and that my painting efforts might ruin them. Then, I had an epiphany. I realized that nobody cared. That when I die, all of my models will only become so much detrius that my family will have to get rid of, regardless of how well they may be painted. So, I decided to paint. And, I must say that my efforts please me a great deal. I think that get better with each model.
Most importantly, I really enjoy painting models! Over the past couple of years, I've gotten five airbrushes and a great compressor. I'm not suggesting at all that I'm a master. I am saying that I realy like painting. At this point, the building process is only a means to an ends - painting. As soon as I figure out how to reset Mozilla, I will post pics of my latest build, a Panzer Mk. IV Bergepanzer. I think the build is OK. However, the painting really brings out the model. Again, it's not perfect, but the difference between the unpainted and painted models are huge.
Go for it! Pull out your AB. Use brushes if that's what you have and are comfortable with them. Start painting your models. Heck, if it turns out poorly, so what? Let's face it, the only people who care are you and a few people on these forums. I'm not aware of too many plastic model museums and I know there are no recognized awards for painted models. Have fun.