Don't stand up. It raises you heart rate up and that isn't necessary. Start into the incline gently. Keep spinning until it becomes too hard then shift down. Do this until you are in your largest gear and don't have anymore. Then just try and keep an even cadence and keep going.

I had to climb but I am training for a big hilly event in September. So I am learning a lot about shifting and candence. Keep it up and you will be a climber in no time!