Great Weapon Fighting class passive: When you roll a 1 or 2 on a damage die for an attack with a two-handed melee weapon, that die is rerolled once.
Savage Attacker feat: When making melee weapon attacks, you roll your damage dice twice and use the highest result.
Lucky feat: You gain 3 Luck Points, which you can use to manipulate either your rolls, or an enemy's rolls.
In addition, the “bless” spell also improves attack rolls slightly.
