97 Cavalier starts running hot when idle. What causes this?

Hello,

I have recently had some work done on my 97 Chevy Cavalier. I had my radiator hoses replaced, my thermostat replaced, and my heater coil replaced. Now, I notice that when I sit idle for a few minutes, I start smelling a hot coolant smell, and notice that my temp guage is starting to rise. I have spent so much money recently, I would really like to fix this one myself. Any ideas would be great!!!

Thanks
Greg