This behavior poster is a good visual for the classroom, so that students know what to expect. To follow this behavior consequence plan, simply cut up some yellow and red card stock (laminate or not, it's your choice). The first time you have to warn a student is a verbal warning. The second time you need to redirect them, you simply put a yellow card on their desk. The final time, you walk by and put a red card on their desk. This signifies that they now have detention.
Please let me know if you have any questions.