Theone... where do we start????
that is a very difficult question that you are asking. reason being, you have not told us what situation you are in with your tank now, and what situation you want to be in the future.
First off... you have a tank..cool... .. what kind of filtration system do you have? do you have water in it now, and if so, how long has your tank been running? do you have lights, and if so, what kind? how many watts? (being as specific as possible will help everyone on this board with suggestions for you...
Second, your best bet is to figure out what you want your tank to look like in 6 months..... with that in mind, figure out what kind of fish / inverts / corals you want in your tank. you dont want to go though the hassle of fixing impulsive decisions...
But, if you are as hard bent as i was...... you can pretty much put in some damsels once you have your water at the right salinity and pH. Although they are probably one of the most hardier fish, plan on at least half of them dying on you......then plan on getting rid of all of them once you have your tank cycled and want to get other fish... there is a good chance your damsels will pretty much kill any other fish you will want.
hope that helps