Here is a way to get dagger experience when in Carvahall, your starting place. When there are Urgals all over, kill them all except for the one near the gold ring. Go to the dragon head and save. Repeat.

Also, Great dagger move: Learn the Strong Combo Finish and Quick Combo Finish Moves. Then go up to an Urgal and press X, X, Y,Y and Eragon will hit the Urgal, hit it again, slice downward, and uppercut. The Urgal will die.