As I mentioned before, could be an ignition switch problem.. if there's no crank.
You can find plenty of ways to test it out, but it basically all amounts to verifying that it supplies power to the starter when you crank it over.
I've never tested out our ignition switches so I can't verify wire colors or the number of them..
But usually there will be a 12v constant (red), accessory wire (different from car to car), keyed 12v (yellow typically), and the wire leading to the starter.
The wire leading to the starter will only receive power when you crank over the engine, so you'll need a test light or DVOM to check it.
I'd start by gaining access to the connector coming from the ignition switch, usually located under the steering column covers, and figure out which wire leads to the starter.
Connect your test light to this wire in the connector, and crank over the engine and verify there's power coming from there..
You can do this same thing by putting your test light on the starter end of this wire which will be attached to the solenoid.. have it cranked over and watch for voltage.
If you're sure that the starter is good, then you may have a faulty ignition switch or a lack of power supply which could come from a faulty or low charged battery..
