When my husband and I were sleep training our first baby we decided to go all in and use the cry it out (CIO) method. Unfortunately, we didn't know any parents who were taking this route, so we felt a bit like renegades and a lot like "the worst parents ever." We quickly realized that in order to survive the gut-wrenching guilt that overcomes a parent when their infant is screaming for hours, you have to have some tricks up your sleeve. Oh, and also, a steely resolve. I recently asked a few parents what tricks they used to survive crying it out, and their answers ranged from the practical to full-on Jedi mind trickery.
For me and my husband, our CIO toolbox included alcohol, ear plugs, and white noise playing on my iPhone (while placed directly across my ear as I slept). We started our first night off with very large martinis to help give the evening a party type of atmosphere. "We're celebrating our imminent liberation from 10 wake ups a night!" The first 45 minutes of crying were probably the most brutal. When our son soothed himself to sleep at the 50 minute mark we pretty much thought our job was done and sleep training was in the bag. Two hours later, it started up again. The crying lasted on and off for hours while we tossed and turned and I imagined all kinds of horrible things happening to my baby. Thank goodness my husband talked me out of going to his room. The next morning, our son didn't look like he was emotionally damaged and was smiling and happy to see us. We repeated CIO for four more nights and by the fourth night he cried for 20 minutes and that was it. (Note: CIO did not work on our second son because all babies are different and parenting is not fair.)
Sleep training is something I cannot imagine anyone doing alone. The common theme among the responses I read from parents is that having a partner to share the experience with is vital to your overall survival. There needs to be another person talking you through it, or holding you back from giving in to the urge to pick up the crying baby you've just let cry for an hour (because that precious babe will probably fall asleep in the next five minutes if you just go a little while longer). It also helps to have someone to celebrate with, weeks or months later, when you're finally out of the woods and enjoying blissful, nearly uninterrupted (because you'll never truly sleep uninterrupted again once you have children) sleep.