So unlike some other forums in the past, this site is more based on trust rather than references.
With some other sites (PokeGym, Pokebeach, Pojo, Pkmncollectors), they use a rating system so that for each successful transaction, users can rate them similarly to how you can rate eBay sellers. It is super easy to know how someone is trustworthy based on the number of references or their score. For instance, someone might have 100 references, but if 10 of those are neutral or negative, it doesn’t really show they are that honest. I think when I left Pokegym, I had near 250 references (I just checked and I have 239 there).
However, like I said this site is not like those ones with a rating system. Instead, it is merely based on trust (which albeit for newer members this is a little scary), that being said the longer you are around here, the longer you will notice the “regulars”. Most individuals on this site are quite acclaimed in respective areas for their business mogul sense around pokemon cards. We have some of the most interesting collectors around, from PSA graders, uncut sheet fanatics, Japanese card database compilers, and foreign language specialists. Once you’ve been around long enough, you will notice the more reputable members have become well established here with many posts (indicated by the number of badges under our names) as well, most have other forms of selling/trading and are generally able to convey that information.
That being said, when you are starting out, look for these individuals. They are well-known and trustworthy so they should be able to help you as you are first starting out and as your “business” grows, you then would be able to assist the individuals who have smaller collections.
Hope this helps!