7 IELTS Writing Mistakes That Keep Students Stuck at Band 6

If you’ve had two or three IELTS writing results come back at exactly 6 or 6.5, the problem is very rarely “my English isn’t good enough.” It’s almost always something narrower: a specific, repeatable habit in how you plan, structure, or check your writing that quietly caps one criterion while the others sit higher. Below are the IELTS writing mistakes band 6 candidates make most often, organised by which of the four criteria each one damages — Task Response (Task Achievement on Task 1), Coherence & Cohesion, Lexical Resource, and Grammatical Range & Accuracy. Each one is specific enough that you can check your own last essay against it today.

What Actually Keeps a Score at Band 6?

A band 6 plateau is almost always caused by one or two of the four writing criteria sitting at 6 while the rest sit closer to 7, because your overall Writing band is the average of Task Achievement/Task Response, Coherence & Cohesion, Lexical Resource, and Grammatical Range & Accuracy, rounded to the nearest half band. The most common causes are: only partially answering the Task 2 prompt, a missing or generic Task 1 overview, relying on a small set of repeated linking words and vocabulary, writing almost exclusively in simple sentences (or attempting complex ones without enough control to avoid errors), and running out of time to check the essay for slips. Each of these caps a specific criterion regardless of how fluent the writing feels to the person who wrote it. Fixing the one or two that apply to you, rather than “trying to write better” in general, is what moves a plateau.

Why Does My Writing Feel Fine but Still Score 6?

This is the part most students get wrong about their own writing: fluency and accuracy under band descriptors are not the same thing as fluency in the sense of “this reads smoothly to me.” The IELTS Writing band descriptors, published jointly by British Council, IDP: IELTS Australia, and Cambridge Assessment English, reward specific, checkable features — a direct answer to every part of the question, logical paragraphing with a clear progression of ideas, a wide range of vocabulary used with precision, and a mix of grammatical structures used accurately. Writing that feels natural to you because it’s comfortable and familiar often means you’re repeating the same handful of safe sentence patterns and words, which reads as competent but narrow to an examiner working from those descriptors. If this sounds like your situation more broadly, our diagnostic on why IELTS writing gets stuck at 6 or 6.5 walks through how to isolate which criterion is the actual ceiling before you start correcting anything.

Mistake 1: Answering Only Part of the Task 2 Question

This is the single biggest cause of a Task Response ceiling. Two-part questions (“discuss both views and give your opinion,” or a problem-and-solution prompt) require every part to be addressed, not just the part you find easiest to write about. A common pattern: the candidate writes two strong body paragraphs on one side of a discussion, mentions the other side in a single sentence, and states an opinion that doesn’t clearly follow from either. The English can be entirely accurate and the essay still won’t clear band 6 under Task Response, because that criterion is explicitly about whether the response is complete and relevant to every part of the prompt, not about sentence-level accuracy. The Task Response criterion page breaks down exactly what “fully addresses” means for each question type. The fix is mechanical: before writing, list every distinct part of the prompt and check your plan covers each one with roughly balanced space, not just the parts you feel confident about.

Mistake 2: A Missing or Vague Overview in Academic Task 1

Academic Task 1 has one requirement that candidates consistently skip or handle badly: a clear overview paragraph, separate from the data description, that states the two or three main trends or comparisons in the chart, graph, or diagram. Many band 6 essays go straight from the introduction into describing individual data points without ever stepping back to say what the overall pattern is. Others include an overview but bury it inside a body paragraph, or make it so generic (“the graph shows several changes over time”) that it doesn’t actually identify anything. Task Achievement specifically credits a clear overview of main trends as a separate, identifiable feature — its absence caps the criterion even when every individual figure quoted in the essay is correct.

Mistake 3: Repeating the Same Three or Four Linking Words

Coherence & Cohesion doesn’t reward linking words for existing — it rewards them for showing a logical relationship that the reader would otherwise have to work out. Essays stuck at band 6 tend to lean on the same small set — “moreover,” “furthermore,” “in addition,” “however” — dropped at the start of sentences almost mechanically, regardless of whether that specific relationship (addition, contrast, cause) is actually what’s happening between the two ideas. The result reads as connected but not genuinely cohesive, because a paragraph can be full of linking words and still not progress logically. Our Coherence & Cohesion guide covers the full range of cohesive devices IELTS credits beyond basic connectors, including referencing (pronouns, synonyms) and logical paragraph structure, both of which matter more to this criterion than connector density.

Mistake 4: Recycling the Same Vocabulary Instead of Building Range

Lexical Resource is scored on range and precision, not on sounding sophisticated. A very specific band 6 pattern: the essay repeats the exact same topic word — “important,” “problem,” “people” — six or eight times across 270 words, sometimes swapping in a thesaurus synonym that doesn’t quite fit the context to try to avoid repetition, which then reads as an error rather than range. Genuine lexical range means using several accurate, natural alternatives across the essay (not one swapped-in synonym) and using topic-specific vocabulary rather than only general words. The Lexical Resource page has the distinction examiners actually use between “range” and “sophistication” — they’re not the same thing, and chasing sophistication with words you’re not confident using accurately usually costs more than it gains.

Mistake 5: Playing It Safe With Only Simple Sentences

Grammatical Range & Accuracy explicitly rewards a mix of simple and complex sentence structures used accurately — not just accuracy on its own. An essay written entirely in short, grammatically correct simple sentences can still be capped at band 6 under this criterion, because “range” is graded separately from “accuracy,” and a response with no complex structures has no range to credit. This is common among candidates who were told at some point that “simple is safer” and internalised it as a blanket strategy rather than a fallback for structures they’re genuinely unsure of. The Grammatical Range & Accuracy guide sets out what “range” actually requires: a genuine mix of structures — relative clauses, conditionals, passive voice where appropriate — attempted with reasonable control, not perfection.

Mistake 6: Writing Long Complex Sentences You Can’t Control

The opposite mistake is just as common and just as damaging: attempting long, ambitious complex sentences that break down grammatically partway through, often because the sentence tries to pack in three ideas with two subordinate clauses and loses subject-verb agreement or tense consistency somewhere in the middle. A single accurate complex sentence is worth more, under this criterion, than two ambitious ones with basic errors in each. The practical fix is to build complexity gradually in practice — one subordinate clause at a time, checked for agreement, rather than attempting maximum complexity in a timed essay before you’ve practiced the specific structure enough to control it reliably.

Mistake 7: Running Out of Time to Check Your Own Writing

This one isn’t a knowledge gap at all — it’s a time management problem that manifests as grammar and spelling errors. Candidates who spend 35 of their 40 minutes writing and leave nothing for review consistently produce essays with careless slips: a missing article, a subject-verb mismatch introduced while editing a sentence mid-write, a misspelled word that autocorrect would normally catch. These are exactly the kind of “frequent errors” that Grammatical Range & Accuracy penalises, and they’re avoidable with three or four minutes of dedicated proofreading focused specifically on verb tenses, articles, and subject-verb agreement — the three error types that recur most in rushed writing.

How to Find Out Which Mistakes Are Actually Costing You Marks

Reading the list above and guessing which ones apply to you is a reasonable start, but it’s genuinely hard to be objective about your own writing, especially the mistakes that feel invisible because they’re habitual — you don’t notice you’re repeating “important” six times because none of the individual instances feels wrong. If you’ve compared your last couple of results and want to see the concrete difference between where you are and the next band up, our band 6 vs band 7 comparison shows real examples of each criterion at both levels side by side. Beyond that, the fastest way to isolate your specific ceiling is to have a recent essay marked criterion by criterion by someone applying the actual band descriptors, rather than giving you an overall impression — that’s the difference between “your writing is good but could be better” and “your Task Response is a 7, your Lexical Resource is a 6, and here are the three lines that show why.”