Search on here actually is a good place to start. Since this tuning area was created a lot of the tuning info was moved here I have not gone to the eectuning forum in years. With the focus on our years already it just cuts down on the filtering out the A9 stuff. If your just starting I would read the basics of the tuning guide sticky and pick items to search on from beginning things to more complex things. There is a wealth of info Grady and Wes have posted.
1. Getting started.
2. MAF, injector, timing and how it works in our eec.
3. Go from there in what area you want to research. From driveability, WOT, N/A, boost, N2O, and idle.