New forum member--how should I vet a seller in the classifieds here?

[surfnli]

Hey all,

First time poster. Looking to make a splash and add to my existing collection and thus far have found some watches I like in the classifieds here. Can someone more experienced than I please let me know what the "best practices" are with respect to vetting sellers from the forum? I already saw the "i love this guy" section--but I am not sure how much credibility you can ascribe to those...

Thanks in advance!