Effective methods of teaching self control in children ages 3 - 7 is through fun activities.
1. Play "Simon Says" or "Mother May I."
2. Encourage children to read to each other (even if they can't read words they can read the pictures) and then you or other child as an audience have the role of listener. Your job is to listen to the story as told and ask a question at the end. Then trade places. Younger children can be given a picture of ears to help remind them of their role.
3. Have children help set the table for meals, rather than them just showing up and finding everything already ready for them.
What other things can you think of that require patience?
There was a famous Russian study back in the 1950's where children were told to "stand still" for as long as they could. They lasted two minutes. When asked to pretend they were "soldiers on guard who were standing their posts," they were able to stand still for eleven minutes. Give them a role.