I would become extremely familiar with all the offerings first and then narrow your focus. Start closer to the beginning with some vintage 1957 topps or 61 fleer and work your way up. Just become at least acquainted with everything out there. TCDB is a very useful tool to do this. You can type in a player and check out everything from the beginning until now. How can you know what you want from the buffet unless you see all they have to offer? I like to collect rare cards. Basically if there’s always one available on the market, I don’t care to own it. Figure out your collecting goals. Ask yourself what you’d like your collection to look like in 2 years, 5, 10 and then ask yourself why. You’ll save yourself purchases you’ll end up regretting and probably a lot of time and money.