There are just a few aspects of life that we can truly control, and it's useful to know just what those areas are. If you don't know, you'll spend a lot of time blaming others for your own failings. Try and exert too much control in areas you shouldn't and the universe will create some interesting ways to remind of your place.
So be prepared an learn the 10 things in life that you DO control:

1. What you do Your actions are yours alone. You choose to make them or not make them and you are responsible for the effects of those actions.
   
2. What you say Likewise, the words you speak (or write) are also consciously chosen. Like actions, they have an impact on your life and the lives of those you contact.
   
3. What you think Yes, there are some subconscious thoughts that you can't control. But the things that you really think about, your beliefs, your ideals, etc. are concepts you have chosen to accept and believe in.
   
4. Your work Many people like to overlook this one, it being much easier to say "Oh, I'm trapped in my job because I don't have a degree, experience, etc." Hogwash! That's simple a way of denying one's responsibility in having chosen the job in the first place.
   It's your job and you chose it. If you stay (or go), that's a choice as well.
   
5. Who you associate with There's a famous t-shirt that states: "It's hard to soar like an eagle when you're surrounded by turkeys."
   Your friends can either lift you up or bring you down. You make the decision which type of friends you wish to have.
   
6. Your health Much of our health is a factor of genetics, environment, and exposure. Much more of our health is simply a matter of the things we choose: diet, excercise, drugs, sleep, routine physicals, check-ups, etc.
   
7. The environment you live inYour house, the condition of your home, the town you live in, the amenities available to you are all things you can control, although some to a lesser degree (i.e., you decide to tolerate them or move someplace else).
   
8. Your finances Having or not having enough money is a factor of what you make versus what you spend.
   
9. Your timeYou choose how to "spend" your time and how much of your time to give to various activities. You'll never get more time than the 24 hours your given each day.
   
10. Your legacy All your actions, words, and knowledge that you share while you are living become the gift that you leave when you are gone.