I would start by doing a lot of research... it helps a LOT when setting up and understanding what goes on in a reef tank. READ READ READ! And then, when you are about to add water and rock to your tank, stop and READ some more. Maybe start a freshwater tank beforehand, to get primed for the basics of aquarium maintenance. Neon Tetras are cheap, colorful, and not overly delicate... 5 in a 10 gallon with basic equipment, maybe a cory cat to go with them. If you can keep them healthy, you're probably ready for a reef tank (though it's... different from a 'fish tank').
THEN, add water, rock, and light to a reef tank setup and with good husbandry you should have all kinds of strange and wonderful critters running around your tank within weeks. But for sure, read all you can about aquariums before jumping in... there's more to it than just feeding the fishes some flakes once in a while. Know what conditions you can provide, and choose your livestock accordingly. Absolutely get test kits so you know what's going on as far as water chemistry, it makes ruling out things when you are having problems much easier. Ask lots of questions, Google is a great tool if you're specific (and if you can't find it there, there's always here. Spelling counts too, at least with Google sometimes
) Once you have something set up, try not to disturb it too often by re-scaping (specially in a planted freshwater tank).
Hmm. I think that's enough advice
If you have already successfully kept FW fishes, then I'm sure you're ready for a reef tank... just be aware, it's addictive.