One of the best ways you increase your self-control is to learn how NOT to use it. That doesn't sound right.
In the book Willpower by Roy Baumeister, he poses the following theory based on his research. Self-control (willpower, self-governance) is a finite energy that everyone has. Since it is finite, you use it in some areas of your life, not others. Therefore, it is imperative that you use your self-control wisely.
Since self-control is a finite energy, pre-decide on how you deal with future temptations and weaknesses. That saves your self-control for emergencies.
How will you deal with your temptations?
Most people think they have more self-control over their lives than they have. And that means it is easy to think you can dabble in questionable actions, and it won't hurt you. It is so easy to believe that lie, and that's why people end up as addicts, prisoners, or relationship breakers.
How many men and women nowadays believe that a bit of porn won't hurt them? It is an epidemic around the world. How about addiction to drugs? People that are addicts now didn't wake up one day and say, "I want to be addicted to painkillers, so let me find some!" They believed a lie that said, "It won't happen to me. I just need to feel different than I do right now."
Or, in business, a little lie about a personal expense on your expense account does not hurt, right?
Each of those examples would have had a better outcome if the person pre-decided because pre-deciding keeps you away from the edge so you don't slide down the slippery slope.
Create clear, unambiguous rules and guidelines.
Pre-deciding is a very simple concept that helps your self-control. The key is honesty about situations that are difficult for you or that you don't want to do or have in your life. Then pre-decide that you will stay true to your good values.
Pre-deciding is about decisions that seem inconsequential, like picking up a hitchhiker, or as significant as monogamy.
Of course, you might say, "I will commit to doing the right thing." While that is very good, it isn't as powerful as committing to a specific "right thing." For example, if you decide you want to be monogamous, what have you decided to do in times you are with a person you are attracted to? You will need to choose what "right thing" needs to happen in that specific situation.
Just like great leaders create and provide clear expectations to develop a structure of productivity and high performance, you make clear rules and guidelines for your behavioral structure. Those rules and guidelines become your first and, sometimes, last line of defense when temptation enters your life.
Strengthened by a sacred command
Finally, Roy Baumeister's research showed that a sacred command helps. When you commit to what God or your higher power says, you increase the probability of self-governance. So, be sure about what God wants you to do and not do.
Pre-decide to follow some sacred commands. You will save your finite self-governance energy for those things that may be surprises.