hold the spark plug to the cylinder head (do not touch the metal!)
got spark? yes or no.
If yes, the move on to next step.
If no, please refer to Fred's Guide.
place spark plug back in cylinder. Kick over a few times. Take out spark plug.
Is the spark plug wet with gas? yes or no.
If yes, please refer to Fred's Guide.
If no, please clean carburator with special attention to small brass jet.
step 3: If all above fails, meaning you have spark and gas, take off exhaust. Try to start moped. Does it start?
If yes, clean muffler by either scrubbing with metal brush or burning out carbon (more instruction on Fred Guide or just search for "cleaning muffler")
if no, please refer to Fred's Guide.
That will fix it most of the time. Fred's Guide is located in the Resources>Articles sections. Even if you get the moped running, please take time to read Fred's Guide. It is a great resource.