I use HR monitoring to pace myself, making sure it not only doesn't get too high when I'm on the switchbacks, but also that it's in the appropriate range when I'm starting out so I don't set out too fast.
Everyone feels their best when starting out, leading to a tendency to go too fast, even though it doesn't feel like they're walking too fast for the conditions.
Another good technique to disciplining your pace is using the rest step. This is usually most beneficial on steep terrain, but if you sense you're jackrabbitting at times on any ascent it can reel you back in to a cadence you can maintain for quite a while without stopping.
