The accuracy part of this should be self-explanatory. Don't pick artillery. Use a tank you like.
You achieve the highest potential damage with shots to the other tanks upper body and turret. Press
in the garage to see your potential damage. Every hit on the upper body of a tank counts as the maximum damage towards this achievement, even if the shot is deflected and actually does no damage. So 1000/(max damage) is the number of upper body shots you must hit with. Once you've made that, you can finish with track shots to reach the 85% accuracy and 10 or more shots fired.
There's no in-game tracker for this, but the sniper medal is slightly more strict, so if you get the sniper medal, you should have this.