There are many free worksheets available, especially online, but still the best worksheet is one that you personally draft. This way, you are able to match the level of difficulty of the activity in accordance to the performance level of your own students. It is not bad to reuse worksheets for another batch of students, but once in a while it is also better to vary the activities you give to kids. Worksheets can be made for fun if it is attuned to the current interests of kids. The kids will respond better to activities close to their own interests.
Worksheet is not just for practice. Teachers can also let their students do a group activity through worksheets. Through this, students will learn how to bond and work with their classmates as one team. Teachers may also make worksheet activities as a contest. The prizes at hand will inspire and motivate students to perform well and learn their lessons.