My view is that if you genuinely want something, it can be done. Enough diligence and enough determination produce a result worth having.
The first message I got from Lien was this: "I'm sitting the exam at the end of this month, how do I get 6.5 in writing?" What actually happened was that she went from 5 to 6.5 over nearly five months of steady work.
Why writing is so hard to shift
Writing is one of the hardest IELTS bands to move. At first Lien struggled to find anything to say. What changed it was turning up to lessons consistently and discussing the topics over and over. That discussion is where complete essay ideas come from, and it makes the material stick far longer.
When you write, stay on the topic you have chosen. Trying to cover several topics at once scatters your attention and you end up applying none of what you have learned.
The four marking criteria
An IELTS essay is marked against four criteria, each worth 25%.
Task Response. Whether you actually answered the question set.
Coherence and Cohesion. Whether the piece connects, flows and can be followed.
Lexical Resource. Your command of vocabulary and everything that goes with it.
Grammatical Range and Accuracy. How flexibly you use grammatical structures, and how accurately.
Beyond those four, a teacher should be looking at individual words and sentences and offering alternative phrasings and more varied structures.
What made the difference
She went from essays covered in corrections, essays under the word count, essays with distinctly odd sentence structures, to work that reliably sat at 6.5.
What she told me afterwards is the part I liked most: "You have to write it, correct it and look at it again before you can see what you got wrong. I started writing and somewhere along the way I got addicted."
That is it, really. Writing has never been the easy skill, and drilling it alone is dull work. But with a group to argue the ideas through, and someone who will mark the finished piece properly, moving the band stops feeling out of reach.