Yup, cafemom for me too it seems like forever ago
I would say shadow instructions, styles or whatever their program needed for them to acheive great shadowing on their layouts.
If that doesn't count . . . .hmm, what is the must have for me?
Flowers...I need flowers and greenery! I can't do a layout with either.
Biggest advice I can give:
Give everything a try
Try out new techniques that there are tutorials for.
Don't give up.
Listen to critique. It can help
I would say classes on how to use photoshop (or other software). Especially with photoshop there's so many possibilities and things you can do. Once you know a little more about what you can do, you also start to know which things you need to invest in (kits etc) and what everyone on GS is taking about Plus most of those software classes come with free kits so you have something to start out with and get a sense what kind of scrapper you are.