For me, a large key to enjoying life is initiative: Setting my alarm clock so I get up when I want to instead of waking up late; sitting down with a cup of coffee in the morning to relax and reflect instead of absently looking at my phone in bed; responding to work email after I complete my big projects instead of letting my inbox run my day; choosing to have dinner with the kids instead of staying at work until "it is all done"; making a list of what I want to get done in a day and doing those things first.
For a long time one of my little traditions has been to make sure I exercise on New Year's Day. It is a small way of mentally setting the initiative for the year, of saying "I'm healthy and active." This small ritual doesn't guarantee anything, but I can look at workout logs for past years and see that, with striking consistency, the mediocre years tend not to have an entry on January 1.
We have all heard the wisdom that you can't control many things, but you can totally control how you react to them. Similarly, you can't choose everything – or even many of the things – that you have to do, but you can choose to make sure you create time for the things most important to you.
A long while back a couple of good friends gave me a painting that said, in essence, "You can be happy once you realize that there is exactly enough time for the important things in life." Seems like a good affirmation for 2013. Happy New Year!