 Here are four free websites that will help you ace your IELTS writing. WordCounter.net not only tells you how many words are in your writing but gives you the keyword density so you can identify repeated words. WriteAnImproved.com from Cambridge gives you task one and task two questions to practice and then you enter your writing and it gives you instant feedback. Ludwig.Guru allows you to enter words and phrases and it will give you synonyms definitions and also show you where that word or phrase has been used in real writing. JustTheWord.com allows you to enter any word and it will show you the most common collocations for that word.