Ask 10 different people and you'll likely get 10 different answers. I've personally found that it simply boils down to what works in your hands. Some stuff that others suggested worked great for me, and others didn't work at all.
All that being said, a lot of folks go with inorganic material (e.g. perlite, vermiculite, etc), simply because it helps to discourage rot, increases moisture control (doesn't really get swampy like soil will), and you will never get a dreaded (and I do mean dreaded) root gnat infestation. However, lots of folks still do mixes with some organic material, but I would stay away from "soil". Peat, coconut coir, pine bark, and other "soil-less" media tends to work best.
My best suggestion is to use a lot of perlite in whatever you do. People who pot up into 40+% perlite (even up to 100%) seem to have some of the best luck. Its light, drains well, its cheap, and its readily available. I had bad luck with 100%, but I'm doing much better with about 50-60% mixed with a few other things. I think my perlite was particularly fine grained, which caused problems (some folks actually sift their perlite to get rid of the fine stuff)
Also, go big or go home with cups! Mine outgrew 16 oz cups very quickly. I'm pretty new to this as well, but I'd recommend using at least 32 oz cups (go to deli at grocery store and ask) with many holes poked in them.
Hope all this helps.