If you have remote start, try and start the scooter. If it does not start, then follow the red wire from the battery to the starter relay, make sure the wire is connected, and then run the red wire from the starter relay to the actual starter. Secure this tightly. Try to start the scooter. If it still won't start, run the negative wire to the ground on the scooter frame and make sure there is full contact and the wire is connected. If it won't start and you don't hear any clicking from the starter, then you probably have a bad starter. Calll our techs at this point and get a starter on its way to you.
One other thing you can check is to remove the housing on the handlebars into which the start switch is plugged, take the housing apart, and make sure the button is making contact withthe switch. If you have remote start and the bike WILL start using remote start but NOT by pressing the button, then you probably have a loose wire connecting to your relay or cdi. Check the wires and make sure they are all plugged in. On a side note, check the spark plug and ignition coil. If your starter is clicking whenever you press your start button, but it does not start, this might be a reason. However, because this is so rare it's almost not worth mentioning.
To check spark (and ONLY do this AFTER you have tried EVERYTHING mentioned above) you will need to unscrew the spark plug from the engine. This can usually be done by removing the panel under the seat. To find it, you will see a black wire with a huge piece on the end plugged into the engine. Take the ignition coil off the spark plug, unscrew the spark plug, and then plug the spark plug back into the ignition coil when it is out of the engine. Hold the ignition coil (NOT THE SPARK PLUG IN ANY WAY OR YOU WILL BE ELECTROCUTED IF IT DOES HAVE SPARK!!!!!!!!) and then press the spark plug end to a bolt connected to the frame (a ground). Then press the start switch. If the spark plug does not spark, get a new spark plug. The plug is an NGK CR6HSA or CR7HSA. Put the new spark plug into the ignition coil and press start again. If it still does not spark, then you probably have a bad ignition coil.