Occasionally over the past few years I would procrastinate things I had to do by casually scrolling through VIRMP listings to see what was out there (it made me just as excited as creeping my vet school's website before I got in used to, and thus was great procrastination). I started seriously looking at places this fall as they got posted, since I had a better idea what I was looking for. What I thought was important to me 2 years ago is very different than what is important to me now.
I have 4 letters of reference; I had never heard that some people recommend 3 instead (I guess I'll have to keep that in mind for the next time I'm applying).
ETA: Similar to above, I let my reference writers know at the beginning of the rotation that I was applying to the match and would appreciate if they could keep an eye on me (at least for those that I didn't already have an established relationship with). I sent my LOI and CV to all of them before they wrote them.
Definitely find some faculty to read over your letter of intent and CV. I had one of my mentors/references as well as a resident friend of mine go over my application to help me fine tune it. It helped a lot!