So

Here are some rules

1. Typically try not to have the same name as canon dragons, or even other fan-made ones in your story. Examples: Snowfall, Anaconda, Thrush

2. Try to not have very many hybrids, or even rarer - tribrids. They're not very common, and a bunch

3. FLAWS. HAVE THEM.

4. Try to write them with realistic relationships with other characters in your story. Their friends and family and enemy are obvious examples, but you should also write their relationships with minor characters. The store salesman. Their teacher. Etcetera.

Will add more as I go along!