A few years ago I used to sleep about 10 hours a night, tossed and turned, and always woke up feeling groggy and was tired all day. After doing a heap of research on sleep I now sleep like a log for 6 hours a night and wake up much more alert, and have a lot more energy during the day, than I ever did on 10 hours a night.
When I first made this change it was hell for the first week but after that my body adjusted and realised it wasn't getting any more than 6 hours a night so it had better make the most of it
I also try and go for a walk every day as sunlight and exercise are natural caffiene for your body, increasing your circadium rhythm which helps you stay up later and sleep better.
I also try and listen to my body carefully when it wants sleep as sometimes I'll be fighting off a cold or virus and my body demands sleep so it can recover. If my body tells me to go to bed early occasionally (signalled by uncontrollable yawning lol) then I go to bed early, and if I'm having trouble staying awake during the day for some reason I go nap for an hour, and then usually just stay up later that night. This week I managed to get over a virus in two days that had my husband home sick for the entire week because I slept and slept and slept. I think sleep is the best possible way you can let your body repair itself.
Anyway sorry to go off on a tangent there
Yes I have successfully reduced my hours of sleep each night. I think the main trick - apart from reducing the hours to force my body not to sleep lazily - has been to get up at the same time every morning, but go to sleep at night only when I'm tired. This lets my body call the shots as it knows how much time it has to do all that overnight maintenance that keeps us healthy.
I hope that helps