If you have a court ordered visitation you MUST document it. This may include having a police officer fill out an incident report. Always keep a copy of your order in your vehicle or with you. Without it it is he said/she said.
Record all conversations. Even is not admissable (check state laws on recording calls) it will help you in the future when formulating your case.
The key to winnig is 2 siple items: 1)document EVERYTHING and 2) win in small steps. The way to lose your kids? Do what Brtiney Spears is doing. Want to win your kid? Document, document, document.