I recommend marathoning a few. I usually watched at lest 3 episodes at a time. The OP also helps a lot since it lists all their names. Trust me, you'll soon have it down.
There's only two characters that I still have trouble telling apart and that's because the look damn similar. One is kind of an important plot point but he's still a minor character so it's not that big of a deal.
Protip for people as clueless as me: This guy is not Luck.