It really depends on the hill that you're climbing. I don't come out of the big chain ring for short little hills and that has helped me, but if you're out climbing long 8% grades then you should probably be in the small chain ring. It all depends on your level of fitness and and riding level to what gear you need to be to top the hills. Good luck!
You want to stay in the chain ring you are most comfrotable with. What you want to avoid is going from the large front ring when you are in at least the largest rear ring. Doing this raises the chances of droping the chain off of the front.
As you ride more you will anticipate what combo you need. Also keep in mind you have many ratios that are the same between each chain ring. So if you think you will need to end the climb in the small ring. Shift to the small ring and smaller rear rings as you start the climb.
Again, all of this will become more natural as you ride more.