What are the best skills for +ATK/-DEF Alm?

If he's +ATK, you should try to run Swift Sparrow or Death Blow as an A slot skill to take advantage of his high attack. For a C slot skill, running Threaten Atk should improve his chances of surviving. If you have it, Phantom Spd will help you proc Windsweep more often. It helps my +SPD Alm out a lot.