What do you do if evap emissions code came up on a 1999 Toyota Corolla?

I would start with the basics depending on which code(s). Is it a small leak, medium leak or large leak? It may be related to the fuel cap or how it seals. It may have a leak or part failure within the evap system. If the cap doesn't solve it, find the local snap on tool dealer and ask him the best troubleshooting gargage for this in your area. He should know. This really isn't a d-i-y kind of thing for most.