I have (had) two approaches to handling hills.
If it's a roller I take a run at it, go hard, downshift as I go up and recover over the top.
If it's a long hill I tend to find a comfortable gear and cadence to the place I am and adjust according to my breathing. I always (attempt) to stay one ring off the biggest. If I fall back to the biggest ring I try to find a place where the grade drops a little to take a rest.