So... to successfully start a reef tank you already have the bascis, the tank, filter, and protein skimmer. Oh yeah have a good heater, and a back up one too.
The other things you need are an R/O unit and a UV sterilizer. The r/o unit to get out those nasty chemicals in yer tap water and the uv to clean all those parasites out of yer water. When you have a reef tank you can't use chemicals to kill parasites because 99% of them will kill yer starfish and other inverts.
You'll need a specific gravity meter and salt also. Read up on what you wanna keep yer salt level at.
Other things you'll need are the live rock and live sand. Get enough rock to kinda set up a wall or lil islan in yer tank. Get enough sand to have about 3 inches under yer rock so yer rock never hits the glass down there and enough for yer inverts to play in.
Also once you get yer rock and sand... you'll need CRABS, and i mean LOTS!!!
Get some red leg and blue leg hermits. This site has some good packages you can get.
Last but not least, always check up on anything before you put it in yer tank.