It's simple...encourage yourself in the Word of God!
The Word of God is so specific and profound that throughout scriptures there are sound bits of encouragement. I know, when you're going through, often words of encouragement is the last thing you want to hear. It's hard to listen to someone say, "It's going to be alright", when you don't have a clue how "alright" will find it's way to your circumstance. That's exactly why it is so important that we walk by faith and not by sight. The way things look will tend to discourage you but things are not always clearly seen with the eye.
Here are some random statements derived from scriptures for encouragement: You are the head and not the tail....it generates that you are significant. You are above and not beneath....this emplies that no matter what happens, you are above these situations and can rise even higher. You can do all things through Christ.....it encourages that as long as Christ gives you strength and is your strength, nothing is impossible to you. Greater is He that is in you....Christ on the inside of you makes you overcome the wicked one of this world. You are a overcomer through Christ Jesus....because of Christ, you have overcame and can overcome every circumstance that's presented to you. You are more than a conqueror.....to conquer is good but your greater than good; no situation will defeat a conqueror. And the list can go on and on.
Nevertheless, you must take the time to learn the scriptures and meditate on them both day and night, in order to remember them and use them in times when you need encouragement. You can't speak victory over yourself if you don't know the word. There is victory through the word of God and victory alone is our greatest source of encouragement.
Now then, you can remember the word, speak the word over yourself, and live the word but none of that helps if you don't believe the word. Believing the word is the tool that enforces the word that gives to you encouragement. If you don't believe the word, you can't be encouraged by the word. And if you do believe the word, it encourages you as it builds you in your most high faith. Faith comes by hearing the word of God and as your faith becomes enhanced, encouragement becomes one of the direct gifts of faith.
So, when someone ask you, "How do you encourage yourself?" Tell them, "By the Word of God." If they ask, "How do you keep encouraging yourself", tell them by meditating on the word of God always. Be encouraged.