I use to be really bad, going to bed between midnight and 1am, getting up between 6:30 and 7:30. Every day I'd feel quite tired.
Since we came back from holiday we've been in bed asleep by 11pm, even if we're just in bed at 10 and "busy" or reading, chatting, wiping clean etc. it's more relaxing than anything else and the next day is frankly a lot easier at work, far more energy.
Regular sleep pattern is vital, even though I have stuff I'd like to do, I still get myself to bed. Weekends are vastly better.
Getting 8 hours now, makes a massive difference from 6-7.