My big recommendation would be making sure you have some kind of case for your singles ... it's very easy to grab cards off a table without being noticed if there are two or three other people chatting up the dealer.
Also, bring plenty of change ... especially 1s, 5s, 10s ... a lot of people forget to do this, and there are tons of buyers who will hand you a 20 for $3 in single cards ...
Another good idea is to bring someone with you ... two reasons ... one, they can help keep an eye on things (especially helpful if you need to go to the restroom or grab some food), and two, it's nice to have someone to talk to.
Also, bring plenty of change ... especially 1s, 5s, 10s ... a lot of people forget to do this, and there are tons of buyers who will hand you a 20 for $3 in single cards ...
Another good idea is to bring someone with you ... two reasons ... one, they can help keep an eye on things (especially helpful if you need to go to the restroom or grab some food), and two, it's nice to have someone to talk to.