Many kids start the school year with the best of intentions, only to quickly degenerate into problems. For example there may be a high schooler with 50 missing homework assignments from the last year, who sets a goal to have no missing homework assignments this year. However, he misses one. Then, he gets extremely frustrated and thinks, I may as well give up! I'm doomed to failure.
In this case, one of the issues was setting a wrong goal. No missing homework assignments was shooting too high. Maybe the goal should have been 30% fewer homework assignments this quarter.
He also needed an achievable plan--what would he do to achieve fewer missing assignments? His plan was: check the school's website to figure out what assignments are due when.
Another issue was not thinking ahead of time as to what he would do if he did miss an assignment. Given his past history, that had a good chance of happening. So, he missed an assignment and immediately had negative emotions that made it hard for him to regroup. If he could have avoided this "crumble," then he could react in a practical way: "I forgot to check the program. So next time I'll set an alarm..."