turn the key on, listen for the fuel pump to buzz for a few seconds, if it does this, then rule that out for now
take your car to autozone, advance auto or whatever and get the battery tested to see if its good and keeps a charge.. you can also have them test your alternator while the cars running to see if it keeps recharging.. but if it was bad, your car wouldn't be eventually starting.. it might for a couple times but eventually the battery would be dead because it isnt getting recharged..
so get those tested.. check to see if its that fuel pump (doubt it) and then come back