Evidence includes a written statement from you and a timeline.
date, time: this happened (see letter 5)
dare, time; this next thing happened (see photo 1)
Evidence might include a print out of texts or emails, with their number written on the top.
It might include your bank account showing no payments from him. It might include letters from third parties - he was late, he did this crazy thing that I witnessed.
it might include doctors letter: she’s reported x to me or y, or a school letter: the kids are late / tired / dirty / whatever
it could include photos of injuries. Or recordings of rants.
all sorts of things depending on what you are trying to argue.
If you are in a contentious situation with a person who is very difficult, he may not tell the truth. Anything you think he will lie about, try to have evidence of the truth.
however, with the best will in the world, most of the time the judge cuts the cake for contact down the middle. So do your best but don’t expect safety or justice to come from a court.
don’t wear yourself out. Keep to the facts.