Yep, try and keep your cadence above 90RPM if possible, if you find yourself spinning slower then change down. Your gearing should be fine to manage this unless it's an extremely hilly route, you could consider a larger cassette if there is still a problem but more likely you're not using as low a gear as you should up the hills.

It could instead be down to poor riding position, maybe seat setback? Although if you feel fine on the flats then this is unlikely.