Can I give you a piece of advice (or many pieces) ?
GO SLOW. VERY slow. This is a (painfully) slow hobby. Once you truly understand AND ACCEPT that you'll have a much higher success rate and more fun.
what do I mean by slow?...well first your tank must cycle. You should get live rock(unless you are doing a fish only then just get some hardy fish...damsels work),1-2 pounds per gallon, and let it sit. for like 6 weeks. YEAH SIX! crazy huh.. I've heard people say theirs cycles in 3 weeks...or even 1-2 with live rock but I don't buy it. This REALLY is (imo) that most important step. If you tank isn't totally cycled and super stable you will be fighting an uphill battle and you WILL -repeat W-I-L-L kill your livestock (trust me on this one). And, in the end, if you don't do this part right, you spend HUNDREDS of dollars and kill every fish and you'll figure out that you need to GO SLOW. (i SO wish someone would have told me this)
So your tank has cycled, now what do you do? Well I would recommend buying a cleanup crew, snails and hermits etc. let it cycle again. 6 more weeks.
isnt' this fun? sucks I know.
OH! and DON'T listen to local fish store people. they WILL NOT tell you to do this step (or few will) they want to sell you fish and will tell you it's okay to add fish when it's not.
SO NOW you're ready for fish. Buy ONE. yep. one. This fish should go in a quaratine tank (QT) , for guess what? 6 WEEKS (okay maybe 4) Actually, you probably could have your first fish in your QT while it's on it's 2nd cycle from the clean up crew and by the time your tank is ready your fish should be ready.
then repeat. Get ONE fish...cycle. and so on.
and one final note - besides reading everything you can get your hands on and all the moderators posts on this board BEFORE you spend a ton of money- seriously do a drip acclamation. Don't float. This site will tell you how to do that in the FAQs.
That's just my opinion. Ive killed more fish than I care to admit so I'm HARDLY an expert. good luck.