GET YOUR DUCKS IN A ROW

Get your ducks in a row - get your affairs in order; organize.

e.g.

Before you talk to the police, you should get your ducks in a row. They are going to scrutinize your story and alibi.

or

Planning To Divorce? Better Get Your Ducks In a Row!

http://sfdivorcecoach.com/planning-to-divorce-better-get-your-ducks-in-a-row/