Consider the difference between these two:
I want to lost 10 pounds this year.
and
Every day, I will run for a distance. To begin with, it will be a quarter mile. Every week, I will increase the distance by a quarter mile.
The first could be accomplished last minute by an extreme diet.
The second might accomplish the first, but more importantly, increases your strength and endurance, and will likely lead to longer term healthy eating.
Create a system which will lead you to your goal, and work on refining the system week over week, month over month to truly achieve your goal.