Now that's a huge question. Depends a lot on what experience you have and what you hope to do with it (it's a bit like asking what kit you need for a freshwater tank, the answer will be very different for a high tech planted or a species only predator tank).
It's a small marine tank, and well below the suggested first tank size, it's not impossible, but people do fall into the trap of trying a small tank to get started and ending up paying for miniature kit and doing lots of maintenance that a larger system could avoid.
So, first questions, is there a bigger tank you can start on to get into marine?
What did you have in mind to stock the tank (fish only, fish or inverts with live rock, full nano reef)?