I'm not a veteran, but I've been fortunate to have some success in my first leagues. I've found paying attention to era to be really important. If the league allows dead ball pitchers, HRs are going to be tough to come by, don't pay up them, and vice versa, if you have a theme league from the 50s/60s HRs can be fine to pay for. I've yet to figure out defense, some people like it, I've found that range is really over rated but that might just be my experience (and I've seen plenty of teams win with Honus 65 error Wagner at SS)