They say hindsight is 20/20, and as a new PSP owner, I'm trying to avoid the "Damn! I wish I knew that 3 months ago" scenario. So have at it!
Post all the neat things you discovered, and wished you knew when you first got your PSP. (I'll keep this post updated).
The most important thing everyone should know:
"I wish I knew that homebrew only runs on 1.0 or 1.5 Firmware before I upgraded!"