Make a mouse over macro for Cover and actually use it. A lot of times it's safer to Cover a DPS or healer that manages to pull off of you and then reestablish hate rather than letting them take a few hits before you manage to get the mob back (especially if Provoke is down). Here's the macro I use:

/micon "Cover"
/ac "Cover" <mo>

Makes it super easy to use the ability since I bound it to a mouse button. I just mouse over a party member and click a button.