Attitude is key. I am an optimist, even in the worse cases I somehow think positively. You have to set goals for yourself and decide that you are going to be determined enough to completely them. If you truly want change you can make it happen. Never be afraid to ask for help if you need it, but you still have to do the work for yourself. Stop holding back and settling for less when you are worth and deserve so much more.
The first step would be to firmly decide that you need to change your life. The second would be to stop yourself from feeling bad about yourself and others that may prevent your progress. The final would be to deny yourself certain things, which may include your current beliefs, desires, wants and goals. In depth, try to talk to people with different opinions than yours and from other cultures and beliefs. This will help you understand things from their viewpoint, consequently giving you a different outlook. Once you find out what you need to change, I'm sure you will find ways to get it done too.
That's a tough one. It depends on what you want to change, I guess. I would start by creating a list of things you would like to do differently, and prioritize them in order of importance. After you do that, you can develop a plan to work towards implementing those changes.