A little clarification about what I said... "Take your time." Completely agree with what Kayla said, nothing good happens fast in a reef tank. I want to comment by saying it can be very hard to resist the temptation to crowd our tanks with new inhabitants and different species, however, this may not give the animals room to grow, which can be a very rewarding endeavor.
We all know this is an expensive hobby, and if you have a lack of funds, it is a lot easier to take your time, than if you have extra disposable income.
Always remember these are living creatures that need room to grow... these animals really do not grow to the "size of their tank" but grow to the size that they are accustomed to.
All of the above comments are very important when setting up a reef tank.