Eat less

6

Considering you don’t have a lot of time I’d aim to lose 1%, maybe even 1.25% of your bodyweight per week. Keep protein high (1g per pound of bodyweight), train consistently and hard, get good sleep, minimize drinking, etc. May lose some muscle but if you do the above some of the muscle loss can be avoided

1

You have 25 days, unless you're right there and only need to lose a few pounds there's no point to this. Just be in a calorie deficit.

1