A friend of mine just asked me--How could you learn to be an Essbase Developer/guru?
I would recommend doing several things.
1. Read Look Smarter than you are:
Sign up for an essbase class, talk with Oracle, and get them to show you their demos of essbase.
2. Make sure that you understand business processes and functions. Form a partnership with business groups, and truly undertand what they are doing.
3. Make sure that you understand technology well. You'll have to understand how to implement ETL, SQL, star schema, and essbase technologies.
4. Make sure that you understand project management. When you're on a project you need to be able to play all roles, Project Manager, Tester, Requirements gatherer, designer, etc..
5. Start using the tool, and get on a project that uses it. Learn by working with others who can teach you the nuances, in a lot of ways Essbase is an art form.
6. Come to my conference speaking session in Orlando IOUG. I will be going over some tips over how to successfully develop and mitigate risks.