How do you stay focused?

Right now I am on a 10-day streak. I know it's not long, but good for me. The longest streak I've ever had is 24 days (I know its pathetic). I've failed constantly. Right now I am finding it easy because I am coming off one of the best weeks of my life. I have been on vacation and thus away from stress and boredom. I want to keep this going forever, but I feel like I may lose motivation and things will get harder. I am wondering what keeps you guys going? How do you keep from falling into a lack of motivation which then leads us to give in to desires?