If you have a class set of whiteboards and materials already, just print and practice with your class.
This two page document contains three white board activities for practicing Ser versus Estar. This is the teacher "script" with the answers included.
Part 1: Have students turn their white boards vertically and write ser on one end. Rotate the board 180 degrees and write estar.
As you call out uses of the verbs, they hold up the end with the correct verb.
Part 2: Listening- Read the statements aloud. Again, students hold up the end of the board that has the verb they heard in the sentence. Ask what form the verb was in and the reason it was used instead of the other verb.
Part 3: Writing- Have students erase their boards. Call out the sentences in English. They will write the sentences in Spanish on their boards then hold them in the air for feedback. Again discuss reasons.
Use these activities as formative assessments as you teach the concepts (preach,pause,practice, repeat), as a mid point check up, or as a review before a summative assessment.