I recently laid our dryer of 22 years to rest after it kept popping the circuit breaker. I know it was just the timer that needed replacing, but the wiring was just too corroded to try to resurrect it one more time.
I'm going to assume that the drum spins and the timer does its thing, as you left those out. The first thing to check is the heating element. Unplug the dryer, take off the back (if it comes off) and you should be able to find it. There should be two wires connected to it. Unplug one of them, then check the resistance between the terminals on the element. If it is open, you found the problem.
If any of that is confusing, or you don't understand it, it is time to call the appliance repair man. It it makes sense, but the heating element is not the problem, read on.
There are a couple of thermostats that control the temperature. If the element is OK, one of the thermostats may be bad. They are a bit tougher to test as they need heat to open or close. This is also where things get dangerous, as you will have to power on the dryer to see where the current is getting blocked. If you can see the thermostats, and they aren't obviously bad (they tend to physically break when they fail), you'll have to turn the dryer on and trace voltages. If you have done this before, you can take it from here. If you haven't, it is time to call the repair man, as it is a bit more involved than can be addressed here.