I'm about halfway through my first kit. Best advice I can give you is take your time. If you need to do something which you're not sure how to do, ask here or google it. I've made a few mistakes with my paint job which, if I had researched first and took my time, I probably could have avoided.
Take photos of every step of the build (before and after) and post them here. Others may spot an issue which you could have missed.
Its good fun, and even though he wife hates all the sandpaper around the house, i'm loving seeing my build come together.