It's so open-ended, and it's also easy to say "Muay Thai, Freestyle Wrestling, BJJ, Boxing, etc". I think, in regards to priorities, other than conditioning, footwork is one of the most important things for a fighter to develop, since so many fighters today have bad footwork. In regards to "weapons" a leg kick and a jab, a double leg takedown, and general ground control, would be the first things I would work on, if I were a fighter. I think you could get by on those things alone to get through the lower tier, and maybe even the middle tier of fighters, if you developed them well enough.