Set yourself up to win...
You aren't going to go from not using the gym to being a 5 X per week gym bunny.
You aren't going to go from a McDonalds eating cola swilling junk food junkie to eating clean 24/7.
You aren't going to even go from a 7 X per week step aerobics queen to a powerlifting program.
You just aren't. Not for any length of time anyway. And the best program for you is the one that you can see yourself doing forever!
If you set yourself unrealistic target you'll fail. Then you forget you even started, sack it off and go back to your old crappy habits. So why not set yourself up to win! Winning creates a snowball effect!
If you have McDonalds for breakfast and a takeaway dinner every day how bout you say you're not ever going to do both on the same day? If you have a McDs for brekkie then you have to cook your own dinner, likewise if you have a healthy salmon eggs breakfast then you're allowed a 'cheat' dinner.
The above scenario won't create a Greek goddess body but they will create momentum. And it's momentum and consistency that gets people into awesome shape.
Think what area of your life you can apply this to. When did you last fail at reaching a goal? Reset that same goal and apply the tip I just gave you.
Hope this help you stay on the New Years wagon (shit that seems a longtime ago)
More love more fitness. No bullshit!