You should make sure you put a lot of thought into the resolution and make it something you really want.
If you are not really needing/wanting this resolution you will not strive to make it happen. Making it something mediocre is already the death of the resolution.
Create a calendar
Mark check point on your calendar and then treat yourself when you reach them.
Make sure it is a goal you can reach
Don't make your goal something you know in the back of your mind you can not reach. Even if you have a larger goal that may take longer, break it down into smaller more obtainable goals.
Not reaching your goal is ok
Make a back-up plan. If you do not reach your goal the first time you try, do not give up. Do not wait until next year either to try again. Have a back-up plan to get right back up.
I hope this helps you out!
Brittany the Producer