Attack other players 1000 times
Make sure you get "Hunter" out of the way first as the bounty reward victories will be much easier against lower level opponents. The best advise is to continuously hunt for people who are classified as 'very easy' or 'easy' as they will be the closest thing to a win and loot. You can of course simply place down on troop member, start the battle and retreat, but this will nuke your glory score.
If you simply want to grind out the achievement, the above strategy of placing a troop and retreating is the single fastest way to attack players 1,000 times.