I have 2 counters for Vets. In a game with lots of vets or if my team is struggling against a few I hope in an oberon Vet. Lot's of people hate of them but they are, by far, the best dog-fighters even an average pilot can literally fly circles around the other 2 classes . . . and this is actually how you win, let the enemy overshoot you, and then happily gun him down with you're 360 fire arc while he tries to turn around for another run.
When i'm not playing a Vet, I'm usually in an Arty cruiser. here's my anti-vet strategy.
1. map awareness. Especially with the new extra mini (useless) mini map I am always looking around.
2. Develop pinpoint accuracy. I fly both the oberon arty (a little) and the murometz I consider my main cannon my main tool for all situations, including vet fights. With the oberon this is very easy. But with the Muro it requires constant awareness so you can bring the weapon to bear in time. I spent a lot of time forcing myself to learn how to hit a vet at close, medium, and (sometimes) long range, depending on what the vet is doing. If you can get them under your guns AND you can hit them consistently your chances of survival skyrocket
3. An Anti-vet module/OB loadout. From the above, I rely mostly on my main cannon(s) and not on modules this allows me to equip my snipers of utility tasks. I typically run dive, anti-missile pulse, bomb catapult, and any of the missiles that strike my fancy (usually scramble). for OB the most important is desperate measures. Here's what I do if a vet closes to weapons range.
-missile pulse the torpedoes
-wait till the dude gets close OR stops and settles in for the kill
-Hit dive maneuver, and while diving target the enemy vet, when he's targeted use bomb cat (for extra effectiveness run module amper and briefly switch energy->weapons while the bombs launch.
If the vet has the audacity to actually ram your ship OR get very close immediately bomb-cat, it's actually capable of triggering on enemies that are close to your ship allowing virtually instantaneous burst damage that's often a 1 hit kill.
If you happen to be weak, mess up, or have already used your modules desperate measures is a 2nd chance to win, it's also a good counter to any vets that happen to have it since it gives you another anti-missile pulse to kill their torpedo reload, full energy for more shields, and another shot with bomb-cat + missiles.
I usually don't bother with my secondary weapons except in certain circumstances that kind of depend on my feel at that particular moment, It's hard to hit with them, the range is short, and I find i'm often able to swing the main gun around which is FAR more effective then several rounds of MG or Flak fire.
Incidentally, if you like a more aggressive arty; this build also allows you to play in a manner more akin to a destroyer. It gives you a lot of survivability and burst damage potential up close, which I've used to flush groups of healers more than a few times or turn the tables on a dreadnought that warp-jumps me without support.
-"Do not bring forth an argument that can be disproved with a 10 minute google search."