Basic behavior contract template.
I've used this with students who needed extra support to correct specific behavior (e.g., coming to the rug on time, keeping hands to themselves, picking up their materials and putting them away).
I find it works well because the student and the parent has all the responsibility and I don't really have to do anything.
Basically, once you've identified a behavior that you need to correct, have mom and dad come in for a meeting. Explain what a contract is to the child and make it sound super serious.
Speak with the parent ahead of time on a consequence. If the student does the specific behavior too many times (set by you), then the child is not allowed to do something really amazing for the evening (screen time usually works well), and if they meet their goal the child gets their reward for the evening.
After a couple weeks, get together for a followup conference and reduce the number of warnings.
After a couple months, the child is usually completely off the contract and needs very few reminders.