I know a lot of people hate them because they make your bow a little more noisy, but I use a peep aligner and attached tube to keep my peep aligned. I have a Bowtech Experience, and I was told that I wouldn't need the aligner to keep the peep centered because the bow has a good string on it, but after a lot of fiddling with it (both by the archery shop and by me), it was still rotating, so I attached the aligner to the peep. I have to have complete confidence in my peep alignment every time, and I use the aligner just to make absolutely certain that I can always see through my peep. That is the last thing I want failing on me in the moment of truth, so I'll take a little extra noise to make it more reliable. I know there are lots and lots of people who can get their strings to where everything lines up perfectly every time, but I haven't had such luck with mine.
If you figure out something that works every single time, and not just most of the time, I would be interested because I don't like the tube aligner; it's just a necessary evil for me at this point.