I'd say KW research too. Try EVERYTHING in your niche in terms of keywords, split test, make notes, work on the winners.
Keyword research is the first thing you need to do when you are thinking of setting up an online business. Doing in depth research in your niche, studying your competition, how you can be better and working around your industry keywords is the first main thing. It is still really hard to rank in a medium-high competitive niche. Unless you spend a lot of money on building High PR links every month.
Affiliate Marketing on the other hand can get any business started right of the bat. I have Jvzoo to be a great platform for any product to launch their affiliate marketing strategies.