Simple budget for a tight month - first time posting

I am $850 short each month and trying to find it. Any experience at all would help. The rent is fixed and the car payment is high. Any apps or methods?

A paper list of bills by due date helped me more than an app. I could see the month at a glance.

Thanks for writing this out. I went through something close to it 2 months ago, and it got easier once I kept a simple log of every call and form.