Don't be afraid to work on contests that has new concepts you are unfamiliar with. Instead, use the contest to push yourself to learn new things (e.g. Protocol heavily uses UniV3 but you didn't know UniV3 before).
"Prioritize contests with larger codebases"
Bigger than 3k+ loc, rather than small ones. Two reasons:
1. The ability to work on large codebases with complicated logic is a must for going deeper in this space
2. Smaller contests tend to have more noise, which may be distracting.
"Spent time reading aside from auditing"
Aside from normal audit work, leave some time for reading articles/write-ups and researching every once in a while. New tech and new issues are popping out every day, it is important to keep track, especially in such a fast evolving space.