Step 1: Buying
Step 2: Tools
Step 3: Fish recomendations
here is a cool fish tank, it may inspire you, or it may anger you, but if it angers you, you may have problems...www.youtube.com/watch
you can go with aggressive fish, like tiger barbs,bala sharks,or pink kissing gouramis. Your probably thinking that because there called aggressive, they'll fight, but when kept with other aggressive fish, they don't. Also, there's algae eaters,and invertebrates, like plecostomus's, otocinclus's( these are so small, they barely do anything, but look kind of cute!), and golden algae eaters(algae eaters) BE CAREFUL WITH ALGAE EATERS,THEY CAN BE AGGRESSIVE AND OUTGROW YOUR TANK, OK? and crayfish, lobsters,and snails (inverts) you'll want a bigger tank for these, I had a blue lobster, and, well, things didn't go so well, I'd go for a 20 gallon tall for these, as lobsters can jump!
TO GET PICTURES FOR THESE FISH http://www.liveaquaria.com