The Fitbit has been my hero for this dietbet. It shows you the total calories burned for the day. I log my food in MyFitnessPal and aim for a 200-500 calorie deficit from Fitbit's calculation each day. Many days I broke even but just tried to not go over.
To me, the calories Fitbit shows that I burn seems pretty accurate so I like that I'm not guessing. I was a stickler about journaling my food so that the deficit wasn't wishy washy. I went beyond my goal weight by a little and plan to stick to this method to lose more. I figured out that making finite changes really makes a difference for me.
Thought I'd share for those who say they're stuck (been there!) and want to try something new in the future. Wishing everyone the best in your final weigh-in. You can do it!!