Even if it's just a little bit. Perhaps go for a quick run around the block, do a yoga session, do a youtube workout video, or even a walk around your local park. Anything, it really does help increase your endorphins!
Write in a journal/diary, write a blog post, or write an email or letter to an old friend. I find writing really helps me, as it completely occupies my mind and gets rid of any negative thoughts I might be having.
Read a new book, read a blog, or even re-read an old book! I find reading occupies my mind aswell, it makes me get lost into a new little world. I even find reading factual books makes me feel more content, as I feel like I've learnt something.
This is probably the only one you'll own moan at, but trust me, it really does help. Whether it's cleaning your whole house, just sticking a wash on, emptying the dishwasher or de-cluttering your room. It'll all make you feel much better after you've completed it (though, a little more physically tired!).
5. Compliment someone
Compliment your family, friends, other half or even a random stranger on the street. Wether it's a physical compliment, or a personality compliment, that person will feel 10 times better about them selves. And you know what? So will you! Knowing that someone else is happy, and that your actions has made them happy, makes you feel better about yourself too.
6. Go a whole hour without a phone/laptop/tablet/tv
I know in this day and age, it's very hard to go without any of these above items. But if you just turn them up for a hour a day, it'll make you appreciate life more. You'll converse with your family/friends more, you'll educate yourself with books, you'll observe your surroundings, and you'll even get some 'me time' that you've wanted!
7. Listen to music
I find just sticking spotify on, and listening to the pre-created playlists, really puts a smile on my face. You can literally get a playlist for any mood you're in; sad, happy, excited, chilled, tired. Sticking on a chilled playlist when I'm feeling a little anxious, really helps calm me down.
What do you do, to make you happy?