Yes, all of the above of what CasaManana said.
Make sure you watch, watch, watch your wares. Even those cute little blue haired ladies have sticky fingers. Ask me how I know? Beware of those that come and talk to you and have someone else with them. They try to distract you as their friend/accomplice will pocket small items. Ask me how I know? Make sure if you have things behind you, NO ONE but YOU can access them them. Those items can grow legs and walk. Ask me how I know? lol
When you count out change to someone. Take ONLY the amount of money from your pouch for change. Have the person that is paying hold their money until you get the correct change out. Then, transfer the money between hands. Don't put THEIR money in your pouch until the transaction is over. It's a HUGE scam that I have had people tell me about that happens. The person/buyer will tell you they gave you a $20, when in fact they gave you a $10. Since you already put the money in your pouch, there's really no way to prove what was given.
Just things to watch for. It doesn't mean that it WILL happen, but always better to be safe than sorry.
But, most of all....have fun. It's a learning experience for everyone!