We humans spend much of our time trying to control every aspect of our lives. Unfortunately, too often we waste time trying to control things that are simply beyond our control.
Having an understanding of what things you do control can make it easier for you to gain control of your life and everything in it.
1. What you do.
Your actions are yours alone. You choose to make them or not make them and you are responsible for effects of those actions.
2. What you say.
Likewise, words you speak (or write) are also consciously chosen. Like actions, they have an impact on your life and lives of those you contact.
3. What you think.
Yes, there are some subconscious thoughts that you can't control. But 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 job in first place. It's your job and you chose it. If you stay (or go), that's a choice as well.
5. The people you associate with.