How can I show my cats they don't have to fight for attention?

Me and my partner adopted 2 cats about a month ago. They are very cute and friendly most of the time and we love them very much. And it seems like they like it here too. But sometimes they tend to fight out of what seems like jealousy. Like if they both want to be pet at the same time, I try to do that. But often one of them hits the other one in these situations so they go away. I would like to show my cats that they don't have to fight each other for attention, but I don't know how to do that. Anyone have any tips for that?