If you want to increase your pulling strength without much effort, get a pullup bar and put it in a doorway in your home. Then just make a habit of doing pullups every time you walk by. This is remarkably effective. I've been doing this for two weeks and have seen significant improvement.

It's important to actually have it on a doorway at all times. Ours was sitting in a closet for several months, and during that time, I used it maybe twice. In the past two weeks, with it actually on a doorway and requiring no effort for me to set up and start using it, I've been doing ~5 chinups every day. (The number has been going up as I've gotten better at it; I'm looking forward to when I can actually do dead-hang pullups.)

$20 on Amazon.

I think a general policy of decreasing the startup cost of doing things you want to do is a useful one. Rewarding yourself helps too, but sometimes you just need to lower the activation energy.