Some things I do since a few years already:
Get up before 7am. Don’t try to fall asleep again if it doesn’t work immediately. Get out of your bed and start your day with whatever makes you happy. Head to work and get home early.
Fixed working-hours. If you have the luxury of flextime it seems tempting to enjoy the flexibility to start and end working whenever you want. However I would recommend that you set your own hours which allow you to do some life-related stuff after work.
A “yes” should be rare. Learn to say no! Say no to friends, say no to co-workers if they ask you for after-work activities (of course you can and should do it from time to time, but it shouldn’t be the norm). Also say no to tasks if you can do them the next day early in the morning. Since a few weeks I try to adapt the Eisenhower Matrix to my workflow.
Find a workout partner. If it feels like an arrangement between a friend/partner to show up at a gym or park for exercising you have to leave the office or otherwise break your arrangement and feel guilty. If you exercise with a friend or partner you can work on a friendship or relationship and your fitness at the same time. Win! 🙂
Cooking and grocery shopping with your partner. This ensures to spend some time together even before couching.
Of course it’s okay to constantly refine your priorities and routines. But in the end it should always help you to keep a nice balance.
Initially I posted this as an answer on Quora.