how to change my sleeping schedule?

[Fortunatus]

since winterbreak began i usually sleep at 3 and wake up at 11 or 12 i just can't go to sleep at ten lol maybe its the twitter and yahoo i should avoid

[Señorita Blue]

This is what I'm doing at the moment. I'm waking up at around 8-9 pm, eat a good breakfast, and within around 3pm, I go for a long jog (30 min max.). Try your best to not take any naps during the whole day. Drink something warm and relax. Remember to keep yourself busy, and to do this again the following day.

[Ava]

Yes, you shouldn't use technology before bedtime, the electronic light affects your ability to sleep for a few hours after that.
Read a book instead.

Exercise half an hour, that will tire you out and help you fall asleep.
However you should do this in the morning or at least 2 hours before your bedtime.
All the best.

[Resnick]

First make a routine and follow it. then able to change you sleeping schedule.