How can you develop great Maximo skills?

If you are on an end user site, conduct Maximo training to staff starting from basic user to power users to management staff. Get feedback on issues and requirements of users and map it on Maximo, this will force you to dig deep into the system. Maximo is the best EAM tool, I have seen.

Focus on maximo developer not user of maximo. 

business awareness and practicing as well as variant customers experience