As far as corals go, get them from trusted sources, dip the crap out of them, and never put anything "iffy" in your tank, no matter how tempting. Both times I got pests (MEN and AEFW) they came from iffy frags.
Fish wise, not a whole lot of options other than set up a QT tank. Honestly, given the size of your tank, if you plan on adding a lot of fish and coral, I would set up a fully cycled and fully functional second smaller tank and use it as an observation tank for both coral and fish. I was going to do that with my 30 until it crashed. The idea was solid though, LOL!
Coral QT is another option, but I would only do that if you were going to consider an SPS dominant tank where the majority of the livestock would be in jeopardy with one little pest.