For myself, I do have a heart-rate monitor, but I've never used it...
I've been practicing climbing over the past few months and can totally vouch for your advice about pacing yourself and not trying to get to the top as quick as you can. That was the mistake I was making, and since I've slowed down (but pedal more quickly), I really do get to the top faster. The improvement is really encouraging and now I hunting out hills to practice on :-)
I'm terrible at climbing hills, so slow it's embarrassing! Never mind, just concentrate on getting up them. I too used to have to get off and walk up some around my local area. Gradually (if you keep going out and cycling the same hills) you'll notice that you are getting further and further up before having to walk. One day, and it will be sooner than you think, you'll get all the way up. OK, you'll feel like a coronary is imminent and you'll be sooooo out of puff, but you'll make it up. Then the next time you get there you'll KNOW you have 'conquered' that hill and it will never defeat you again, and slowly your times will improve. They will -honest!
The other thing that helps with hills is losing weight. I've bought myself a carbon framed bike, (because I have no will power) which has helped enormously, but losing weight yourself is good too! The more hills you climb the more weight you lose, which helps, and of course you get fitter.
I used to dread hills, but rode in a flat area a while ago and actually found it boring! Also the views are great, so treat yourself to an eye full once you get up there.
I'm so happy today. I keep going to this steep hill but i always go down but today I made it! and I've learned to shift my gears better i think that helps alot. I'm not so fast but i concentrate on a steady pace. My next challege is a longer steep hill. I am always amaze to see cyclists who pedals so smooth on this particular hill for my next goal.