I agree with mslily, the best things to do, are things you are interested in.
Another tip would be to find a market before you go searching for your bargains. Even if you find a really cheap deal on something, it's going to be useless unless it sells, so look for stuff that is selling, but has little competition, or you know of somewhere where you could get the item cheaper.
Also, DO NOT GET GREEDY. This is a big first time mistake. Even if you only make a few dollars profit, it is still profit, and the experience is invaluable.
Hope this helps.