How to approach a new project?

I'm trying to work out the best way to approach a new project, and would appreciate any suggestions/"beware of"s from the experienced PHPers out there. I want to build a project where I can enter data from a gym routine online and generate graphs of the data. I'm not familiar with GDLIB, but is this something that can help generate a graph from mySQL data? Is this project feasible/realistic for a new PHP programmer? Also, any suggestions on the structure of the mySQL database would be appreciated. The general data that would need to be input would be: Date Group Exercise1 Ex1Weight Ex1Reps Ex2Weight Ex2Reps Ex3Weight Ex3Reps Exercise2 Ex1Weight Ex1Reps Ex2Weight Ex2Reps Ex3Weight Ex3Reps etc... Plus several calculations would need to be made, which I could presumably do with PHP when I extract the data. Any/all suggestions on how to plan this process would be greatly appreciated! I'm hoping to have a sound game plan for beginning this process. Thanx! Wm luvs2shootAThotmailDOTcom