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.
Worksheets can be a fun activity for the students. A teacher can easily allot a work to a group of kids on through these worksheets. All this can help a student to learn and write in a fun way and even teach him/her how to perform in a team and forming social bond with other kids.