I think of a number I want to earn in the new job. For example, if I would currently make 100k, I say I currently make 115k in my current role, and then they offer 120k. I accept, done.
I did this after a bad experience. Made-up numbers. They offer me 80k, I already make 90k, I say I already make more. They ask how much, I say 90k, they say we can match that and one more week of vacations. I give them a pass, they ask why, I say I got another offer for 110k, they say we could have given you 110k too.
If they are allowed to lie, I can too.