Car is turning but will not start

So the engine is turning over just fine when you hit the key but it does not start up and run.
The first thing to look at, is the security light on while cranking the engine? If yes you may have a bad key or other security issue. When you turn the key on does the check engine light come on? That would indicate that the ECU is at least getting power.

Which engine and transmission does it have? It will not be of a benefit if I tell you to try engine starting spray to test for spark if it is a diesel engine.