>>53498772read ability and moves descriptions if you haven't
Aegis does a lot of damage from basic boosted attacks, but its boosted attack mechanics work differently from others'. Moves like Wide Guard will also give you boosted counts to unleash boosted attacks. People also tend to farm wild mons using moves and save boosted attacks for enemies (unless there's no enemy around). You should also enable boosted attack count interface option in settings.
As for the build, you can use matchcord emblem set. And iirc I like to use Focus, Scope and Cookie or weight, but in all honestly it's been a while since I performed good on Aegislash