Try not to go by yourself. Especially if your ex brings along community members, even YOUR family members - it’s better if you go to court with a friend or at least one more person.
Whatever you do in court - remain composed, stay cool and DON’T explode! The judge is looking to see ‘who looks sane’. Be prepared for the other attorney to say horrible things about you because that’s what they get paid to do. It will be really painful to hear them say nasty things about you, often outright lies, however just be reassured that judges are used to these sensationalized games and ignore the gossip. They are really just trying to listen to the facts and who is the most stable parent. Therefore if you can show that you are keeping things stable at home, kids are content and not hearing negative things about the other spouse - that’s what they will believe.
When possible, try to get the court to mandate court-ordered therapy for the kids. This is because the social workers most likely won’t be orthodox and the kids will have a chance to express normalcy and expose the insular ghetto they live in, etc.