Meditate - Practiced since ancient times, meditation is a great way to detach. Thoughts may run through your mind, but choose to ignore them, and simply be.
Exercise - Working out is good for both body and soul. You will be in a better physical shape and mental state.
Smile and laugh - A surefire way to make you feel better is to smile and laugh.
Watch a funny movie - Going to see a movie is a great way to temporarily absorb a different reality. If comedy is not your thing, then an interesting drama or thriller will also do the job!
Work towards your dreams - It doesn't have to be an unrealistic concept to have dreams. Taking small steps to making your dreams a reality is a hugely positive move and you can start today!
Try dancing - Whether alone or with others, let go of your self-consciousness and let yourself move! Not only is it a good form of exercise, it will also put you in a relaxed state of mind.
Daydream - Sometimes it is good to allow yourself a few minutes out of your busy schedule to just sit back, take a breath, and daydream.
Gratitude - Expressing gratitude allows you to focus on the good things in your life, and concentrate less on the negative aspects.
Be inspired by others - Reading inspirational stories, whether they are fact or fiction, is a great way to maintain a healthy and happy perspective.
Be around positive people - Surrounding yourself with positive, like-minded people is a definite route to happiness.