The main thing is to build your skills, regardless of what skill level you're at. Don't be afraid to try new techniques. Even if it doesn't turn out well or you fail, you still gain knowledge and experience.

The other big thing is give yourself plenty of time. If I could change one thing about I handled the contest, it would've been to start earlier. The GBWC is announced months in advance (and technically, you can still enter this year's competition, just the in-store events are done), so you'll have time to plan and execute.

The last one is if you're interested in entering, go ahead and do it, even if you don't think you have a chance of winning. It's still a good experience, you can meet other builders, and if you speak to the judge(s) afterward, you could get feedback on what to look out for and what to focus on. You also get a cool pin for participating.