Being an exotic vet is definitely a niche career but also one that has services hard to come by. I used to rescue lizards and believe me, it was hard to find a decent vet to bring them to. First off, obviously finish high school and get good grades. Then, go to the least expensive college you can go to and get good grades. Then go to the least expensive vet school possible (in-state?) Do a rotating internship after vet school, and make good contacts. Apply for a get a residency, and do well. A lot of people find that it's very expensive to get educated to become an exotic vet, especially since it can take an average of 8 years after getting your undergraduate degree, which is why you might want to consider going to less expensive schools. They're virtually the same process.
I used to rescue a lot of Bearded Dragons and at one point had a vet who had studied them in the wild in Australia, which was a big plus. There are several programs and internships you can apply for that will help you study in the wild. Even volunteering or doing an internship at a zoo is a big plus. Also, with anything, always be networking and making friends with everyone you study with, do internships for, and work for. They will help you with more contacts as well as opportunities you'll be interested in. I hope this helps!