Understand what you really like. This is the most important, and the most difficult. There will be a separate big talk about this, but the golden rule is - do what gives you real pleasure, and then you will become much happier.
Refuse the garbage you eat, drink and smoke every day. No secrets and cunning diets - just natural food, fruits, vegetables, water.
Learn foreign languages. This will unrealistically expand the depth of perception of the world and will open unprecedented prospects for learning, development and career growth. Knowledge of English - this is not just a whim of the intellectuals, but a vital necessity. Books, movies, audio courses, news, the interface in the phone - just load into the language with your head, and progress will go very quickly.
Read books. The golden rule is read / listen at least one book a week. It's 50 books a year that will turn your life around. Spend on every weekend. Go to the museum, to the exhibition, go in for sports, go out of town, jump with a parachute, visit your relatives, go to a good film. Expand the zone of contact with the world. When you have already traveled around and walked around, take friends with you and tell them what you know. The main thing - do not sit still. The more impressions you pass through yourself, the more interesting life will be, and the better you will be able to understand things and phenomena.
Fix your thoughts. You can start a blog, or you can just write "on the table." It's all about what. It does not matter that you do not have eloquence - the main thing is that you can think and reason that way.
Give up the computer games and useless on the Internet. Minimize the seat in social networks (until optimization - leave only one active account). Forget about the TV, except for popular science programs. Get in the habit of checking mail only at certain times.