if you have all the electronics working inside the cabin, it may be a starter issue(if it doesn't crank at all)
if not :
if you have a volt-meter, check the voltage on the battery.
if you don't, try jump starting the car using jumper cable and another car(or good neighbor)
if it starts with somebody's help, your battery might have been dead. (time for new battery?). but you might want to run your car and charge the battery and see how it holds up first, as you might have forgotten to turn off interior light/heat/exterior light last night.
but as you say, it may very well be the corrosion at the contact points. I would take it off the battery, clean it with wirebrush(with no fluid), put some die-electric grease if you have some(just tiny bit), and put it back on. tight.