I pick up the pace a little bit to get a little momentum, and shift down as the climb progresses to keep the same cadence. When it becomes to steep to maintain cadence, I get out of the saddle.
This weekend is my first on the bike after the winter, my regular loop has a climb in the middle, and today I was standing to get over it. In 3 weeks I'll be able to get over it without getting out of the saddle. In 6 or 7 weeks I'll be able to climb it without shifting down. There are a few grades in my area over 15%, but thankfully they are not long.