I'd start by searching the site here and identifying what you want your tank to look like first.
Then get the equipment- better lighting, driftwood or rocks or whatever, some CO2 (even DIY is cheap and easy and effective), ferts, and then get the plants that match the tank you want. And presto!! just wait and let the tank grow! (the waiting is the worst part)
check out this thread http://www.plantedtank.net/forums/sh...ad.php?t=99729
the tanks with only 2-3 types of plants I think look very clean and take a lot of the thinking out of the process