Take an hour to sit in a quiet room without any stimulation. You'll learn a lot about your mental situation, and understanding where you are is really helpful for understanding where to go (if anywhere).
But what helps me is taking walks. You're alone with your thoughts, but the act of walking through nature is stimulating for more positive thinking, from my experience anyway.
Heh, shit, if that counts I "meditate" for an hour or more a couple times a week. It's absolutely horrible.
[EDIT] in fact, running with that, most of my life has been a struggle to "meditate" less for the sake of my own health and sanity. I'm way down from the every single night for like two damn hours of ages ~7-16!
That is not meditation though. Learning to meditate has helped me a ton in being able to calm my mind down and get to sleep. I'd recommend checking out the Sam Harris Waking Up app, just do it for a few days and see if it clicks.
That sounds like a good start. Learning how to let go of ruminating thoughts is still a struggle for me, but when it happens it will change your life.