"I'm going to lose 5 pounds a week by exercising an hour every day."
Uh, good luck with that. Instead of going big, go home and do something reasonable. If you haven't been exercising at all, resolve to go for a daily walk, or exercise a couple times a week to start. Instead of resolving to cut out dessert, the APA suggests you "try replacing dessert with something else you enjoy, like fruit or yogurt, instead of seeing your diet as a form of punishment."
Don't change everything at once
The "new you" doesn't have to be COMPLETELY new in January. As you list your goals for 2016, attack one behavior at a time. Maybe cut down on sweets in January, and once you've started to get the hang of that, move on to less booze in February, start jogging in March, begin piano lessons in April, clean out the garage in May, learn Spanish in June (wow, that's some list you have).
Don't go it alone
Verbalize your goals to others who will support you, and maybe some of them will go on the journey with you. I'm part of an exercise group on Facebook, and I find inspiration from others doing the same thing helps me stick to my workout program better. I also have more discipline when I know they're expecting me to update them on my progress. Also, if you feel really overwhelmed and unable to move forward, the APA suggests you seek professional help. No surprise that a group of psychologists would recommend therapy! However, "psychologists are uniquely trained to understand the connection between the mind and body," the APA points out. "They can offer strategies as to how to adjust your goals so that they are attainable, as well as help you change unhealthy behaviors and address emotional issues."
Failure as an option
News flash: You might backslide. Maybe you already have (says the journalist eating McDonald's fries while she types this). To err is human. But don't beat yourself up about it, cautions the APA. "Perfection is unattainable." When you get off track, get back on and move forward, because "everyone has ups and downs." OK, just one more fry. Done!