Depends on bike.
If its fuel injected turn it off, wait a couple of minutes and try again. If its got carburetors its probably flooded. You could try starting it on full throttle (will rev real quick if it fires so be ready to drop rpm) or wait at least couple of hours before trying again.
If they are easy to get to you could try taking spark plugs out and drying them
It would be real helpful to know what bike it is?
