Somthing else that works for me is to let the guitar sit for a few hours or even overnight before really playing em'. I'll re-string, tune,stretch,retune,double check the intonation,re-tune, and give the strings a few hours to "set", re-checking the tuning every hour or so. I'll just grab another guitar to play while the new strings settle in.
I learned about this from an old Guitar Player article by a Bluegrass picker named Dan Crary who lets a freshly stringed acoustic sit for two days before really playing on new strings. Two days is a bit extreme, but the idea seems to work,YMMV.
I've played on 0.11's for about 15 yrs and if I'm patient and bide my time before really reefing on a new set, not only do they hold their tuning, but they seem to break less often too. I'm using a 0.10 set on my #1 right now,(an Americian Ash Tele, this thing is a chickin pickin machine, and the slightly lighter strings really bring out that Nashville/Brent Mason wiry twang) ,and this method is even more crucial since I've "wussed out" (lol) to 0.10's.
My Strat is a MIM 60's Strat, and with the Kluson tuners tuning is even more of a chore than with say the tuners on my Tele's which are the modern style with the tightening screws on the tops of the keys. (BTW, my Strat is set up w/ 0.10's too due to the vintage fretwire and the neck itself,which dosen't seem as hearty as my Tele's. The bridge is tightened down as much as it can and I never use the Trem.)
If all else fails, you can always try moving up a string guage. Heavier strings (for me anyway) seem to hold tuning better.
Hope some of this helps.
Ian