In my experience, no one uses Excel to its fullest potential. It's cool. You're in the majority with regard to that rule of thumb. However, I'll give you a list of books you may peruse to help you get a solid foundation. These books contain easy to follow examples and tutorials and some come with discs for practice spreadsheets and stuff.
By John Walkenbach (Mr. Spreadsheet):
Microsoft Office Excel 2007 Bible (A must have if you want the basics)
Microsoft Office Power Programming with VBA
Microsoft Office Excel 2007 Formulas
Microsoft Office Excel 2007 VBA Programming For Dummies
I've used each of these books heavily from everything from trend analysis, to creation of macros, and reporting. You will learn many things about pivot tables, lookup tables, etc.
If you have access to classes, of a practical nature, either company provided, or on your own dime, SkillSoft runs the gamut of Excel training and other Microsoft applications.
Just remember that not all versions of Excel play nice together, especially with macros, and be very careful about which classes you choose. Also, be very sure about the specific application that you are going to apply to Excel as it relates to what you want to learn. If a class says "Advanced Excel" make damned sure you know what is in the class as it may not cover what you want.
Hello Dear, you can learn excel online at your own pace.On the internet you can find so many websites which are providing basic and advance excel knowledge online. I do know one organization which provides online excel training and you can visit them at Excel Training Courses
wow, i forgot about this thread. I have since learned a few function and helpful tools/organization techniques. I'd say I'm doing above par for still being in high school.