Funny. I was just thinking about writing a hub for this!
1. Do the lights turn on? If yes, go to step 2. If no, then either a bad battery or bad connection to the battery.
2. Is there gas in the tank, and if applicable is the petcock on? If yes, go to 3.
3. Does the starter turn? If the starter barely turns or does not turn at all, either the starter is bad, or the battery is dead. If the starter turns, your battery is not dead. Go step 4.
4. Is there a spark? You know there's spark if you hear a pop. If it pops but doesn't start, then check spark plugs and ignition coils. (Checking ignition coils requires a continuity test.) If your spark plugs are ash gray or black, clean them off and reinsert, then try starting again. If it still doesn't start, go to step 5.
5. If your bike has carburetors, is your choke out? Gasoline needs air mixed in (oxygen) to create explosions. If your bike is sitting in cold air, do not turn the throttle when starting, because turning the throttle will bring in the cold air, which will kill the spark.
If after all these steps your motorcycle still will not start, have the fuel intake (carburetors or fuel injection) and your ignition checked including ignition coils if necessary. If those are okay, it might be your stator coils, which charges the battery. On some bikes, especially older bikes and bikes with a lot of electronics, bad stator coils will cause the bike to stall.
You might be able to start your bike by push starting it, if you don't have a kick starter lever. If you're alone, get the bike to the top of an incline and let it roll, or have another person help push the bike from behind.
Have the bike either in 1st or 2nd gear and with the clutch lever held in. After the bike has speed (between 3-10 mph), slowly let the clutch out while giving it some gas.
If you're going to push start it, make sure the road is clear (of course). Also try to avoid gravel, sand, oil in the road, train tracks, or anything else that would cause you to lose traction. Don't forget your kickstand. Some bikes will start at only 2 or 3 mph, but depending on the problem, the more speed you have, the better.
I would write more check tips, but I think that calls for an entire hub.