Put your goals in writing
High achievers have goals and plans. Underachievers live in wish mode. Start with "stretch goals" that are both a reach and reachable, so you may accumulate a confidence-building series of small wins. Nothing becomes a goal until you write it down.
Use the language of change
Tune into the messages you send yourself. Eliminate "weasel words." such as "I will try sometime" or "I will start soon" or "I hope to," and declare what you will do positively. Switch from saying "I have to" and "I should" to saying "I will." Challenge automatic negative assumptions, such as "I couldn't do that," by asking yourself, "Why not?" Try to neutralize irrational fear.
Take baby steps
Think of one small thing you may do today that will make you feel better tomorrow, such as walking a mile or doing some pushups. One daily change, especially if it helps you finish something you started, may change the trajectory of your life.