Sometimes people start by forcing themselves and say, "I will do this no matter what." When it does'nt work, people give up on themselves.
It is important to befriend yourself and ask what are your true goals in life; what are the moments that opens your heart and make you feel elevated.
If something needs to be done, persuade yourself with the reasons for doing it; if one part of yourself is not convinced, get it sorted out, don't brush it aside. Really think through the reasons and the counter arguments you give yourself; reason out the costs and benefits; write them down and repeat to yourself regularly. If there is a little bit of self doubt or doubt about anything and you go ahead, that bit will surface to sabotage you, therefore it will be unwise to brush it aside.
Your self is made up of many parts such as memory, ego, reason, subconscious and others, get all parts of your mind to come together with reason.