If you hit start then hold RT you get your character info screen. On the top left there are 5 colored runes. Underneath that it says accessory item effect then have 2 stats with colored runes next to it. So just equip stuff that has correct color. You can see the runes each equipment piece has by scrolling through your different things.
You have to have a ring with 2 skills on it to have it work bc that's where the item effects come from.
I am crusader but I think the info screen would be the same for all classes.