DON’T WRITE TOO MUCH!
For the IELTS writing tests task two essay you must write a minimum of 250 words. If you fail to do so there is a minus one penalty for your task response. However, there are also consequences if you write too much, as follows:

1. You might not finish both writing tasks
2. You have less time to proofread your task and there is more to proofread
3. the examiner might consider the total number of errors with vocabulary and grammar and not the percentage of correct versus incorrect writing

See more common mistakes for the writing exam.