There are three main components to check:
Fuel, Spark, Air
Pull fuel line off and see if there is fuel in the line. If your fuel pump is bad, there could be some fuel in the line, but no pressure/fuel flow to start the engine. If there is no fuel, then you found your problem. If there is fuel, put the line in a water bottle and crank the engine for 2-3 seconds. If there's fuel in the bottle, then you are getting fuel.
Pull a spark plug wire, put a screw driver in it and place the screw driver near, but not on, a metal part of the chassis. Have someone crank the engine. If there is a spark jumping from the screw driver and the chassis, then you have spark. You'll need to be pretty close to the chassis for the spark to form.
If you have a spare spark plug, you could put the plug in the wire and then touch the metal threads the chassis for ground and see if there is spark.
Check the air filter. With the air box open, go ahead and try starting the engine. There's usually not much for air to prevent starting, but if the sensors are bad, then there could be an issue of not reporting the correct air flow.
Aside from these, you'll have to do diagnosis of sensors, which usually will be reported to the computer. You can check if any codes are being triggered with a scan tool.