IELTS Writing tips
It is better to write in regular, not very sophisticated English, than to use phrases or structures you don't fully understand.
If you need Band 6 - no need for complex sentence structure. If your goal is Band 7 - then show advanced sentence structure, language and vocabulary.
Don't write more than 260-265 words in IELTS Writing 2 task. Why? Not because you will get lower mark, but because of these 2 reasons:
1) It takes more time
2) More words = more mistakes