Bebpo, here are some suggestions:
1. Use a razor blade to get rid of those plastic nubs on the sides of some of the pieces. I'd also suggest picking up a small cutting blocks to work on.
2. Use some sand paper to get the rest of the plastic nubs gone.
3. I have some fine-tipped Sakura pens that I use to do my paneling, it really goes a long way to make the models look even better.
4. Once you're comfortable with the 1/144 models, get yourself a Master Grade (1/100) kit. They don't require painting, and look incredible.