As far as making it stronger there are neck exercises, but as a football player most of your neck work comes from playing the game and wearing a helmet. Having very big and strong traps is a must beacause they help to stabilize the neck when you flex or bow up to hit someone. So for football at least trap development is important.
some things you can do are:
wrestler bridges w/ or w/o weight
4 way neck work with a partner
hise shrugs seem to simulate the neck involvement on football
you could attach a harness to the cable crossover or a sled and use that