Lighting and maintaining the proper parameters are going to be your biggest items. I use MH retros from hellolights, but there are several different types of lighting that can be used, like T-5, LED, etc.
I'm not sure how much checking of water parameters you currently do. Fish can survive in higher levels of PO4 & NO3 than corals. Plus, you'll have to start maintaining the proper Ca, Alk, pH, Mg, etc.
I'd recommend getting a descent oversized skimmer. Not sure if you already use RO/DI water, but for a reef it's highly recommended. Plus, was copper ever used in your tank to treat diease? If so, that could be an issue.
If you want to convert, don't let the above discourage you. I converted mine and I'm very happy with it. I just don't recommend you jump in without being prepared first, which it seams like you're started to do now. Good luck.