The first is pretty self explanatory. Apply planes, pew-pews and torpeedus to the enemy fleet before they do the same to yours. BAM. Win. I think this is the combat result most of us are pretty comfortable with because the rest of it involves math... which probably explains why so many teams have someone on their roster who can't be bothered to appreciate the subtleties of the other victory conditions. It might also explain why some players keep trying to push for wiping out the enemy fleet but pay no heed to the other factors which may strip them of the time needed to win this way.
In terms of accumulating points, while a cap zone will not deplete the enemy's victory points, they are still highly valuable. When you have a 1-cap advantage on a two-cap Domination map, this is the equivalent of sinking an enemy ship every minute. For a 2-cap Domination, this is the equivalent of sinking an enemy ship every 2 minutes & 45 seconds.