How do I get myself to stop constantly thinking about them?

Distraction, distraction, distraction. Obsessing and old habit are your enemies - stop looking them up on FB or following them on twitter, watching their instagram or baiting mutual friends for 'tidbits'. Even just pondering 'what are they up to the moment? Who are they with? Are they happy?". And avoid things you 'used to do together'. Find a new restaurant/cinema etc. When the urge comes upon you - quickly do something else (even really mundane things like brushing and redoing your hair, applying a coat of nail polish, doing the dishes, putting in a load of laundry, sorting a work desk draw, going to the bathroom and reapplying your make up, do an exercise routine) ANYTHING which requires your concentration and attention. Breaking the chain with Action is the best way to wean yourself away for constantly thinking about someone. You are literally training yourself out of a the habit of giving someone your energy and attention.

In my experience, keeping busy with the things I like to do- like meeting new people, drawing, reading a book- will keep my mind off of things I really shouldn't be thinking about. Enjoy your time and do you.

Distract yourself and focus on something else. Do things for yourself. Create something, watch something, play something. Let yourself move on.

Its not easy to forget someone we care for and often we replay events in our mind. The best way to stop thinking about them is to look to the future! Always plan something to look forward to! It could be dinner with friends/family, a good book or movie or just a day spa treatment at home. You could also try planning time in the evening to write or think about that person. Set an alarm for a half hour, shut off your phone and all technology and allow yourself to deal with your feelings. Have a pity party, listen to music or write about what bothers you. Once that half hour is over, then you have to be done! While this may seem hard at first, you will see that the time you spend will eventually become positive and you will be planning your weekly events and other fun things. It also allows you time to deal with your feelings so when they pop into your mind at bad times, you tend to dwell on them less.

Try and Keep busy, find something positive to do like a hobby to distract you... It worked for me!!!

I find it best if you keep yourself busy. Go watch a movie with friends or even just go outside and do something.

It's going to be really, really hard, but essentially you need to start thinking about something else. Distract, distract, distract. Do things that require your full attention.

distract yourself and do something that makes you happy ex: painting or hanging out with someone close

go out for a walk clear your mind ,go see a movie , enjoy the fresh air , call a friend to hangout , you will feel better sooner then later.

Stay busy :) Hang out with other friends, or make new friends all together. Make better friends with yourself Go on new adventures and force yourself to live in the moment by creating environments that you don't want to leave. Personally, I like to go exploring, especially by myself. I find it a great way to come to terms with who I am and what I'm feeling while simultaneously being distracted by the new place. With time it will be easier.