Hello!
I used to not be that great of a builder, but with creative building servers I have become pretty good!
The reason most creative builders are legendary is because they either had natural talent or had practice. Creative servers with a custom rankup system are usually the servers that shape amazing builders. This system is based on skilled buildings that, when requested, an admin or moderator will come and review. Then the staff member will either promote the player or give them tips on how to make their build better.
A perfect example would be the server Mithrintia, who's staff is kind but challenging to your builds.
Anyways, this may be short but I'm just saying that if you're not that great a builder, you may want to consider joining a creative server.