IELTS Writing has two tasks, and Task 1 comes first — 20 minutes, at least 150 words, worth a third of your Writing band score. What you're asked to write depends entirely on which version of the test you're taking.
Academic Task 1 asks you to describe visual information: a bar chart, line graph, table, pie chart, diagram, or map. General Training Task 1 asks you to write a letter responding to an everyday situation. The two have almost nothing in common except the time limit — so know which one you're preparing for.
Academic: describe, don't explain
This is the mistake that costs candidates the most marks — Task 1 Academic is not asking why a trend happened, only what the data shows. Don't speculate about causes unless the source material states them. Your job is to identify the overall trend, then support it with specific figures.
Academic: the four-paragraph structure
Paragraph 1: paraphrase the question in your own words (don't copy it directly — that costs you). Paragraph 2: one overview sentence stating the one or two most significant trends, without any numbers. Paragraphs 3–4: group and compare the specific data, organized logically (by category, by time period, or by highest-to-lowest) rather than just listing every number in order.
Academic: the language examiners are scoring for
Trend language — increased, rose, climbed, declined, fluctuated, plateaued, peaked at, bottomed out — used with accurate prepositions ("rose to 40%" vs "rose by 40%" mean different things). Comparative language for tables and bar charts — significantly higher than, roughly double, marginally lower than. Mixing these up is one of the fastest ways to lose Lexical Resource marks.
General Training: match the tone to the letter type
Formal (to someone you don't know, e.g. a company or landlord) uses "Dear Sir/Madam" and no contractions. Semi-formal (to someone in a professional relationship, e.g. a manager) is polite but can be slightly warmer. Informal (to a friend or family member) uses "Hi [Name]" and natural, conversational language. Using the wrong register for the situation is graded as a Task Achievement failure, not just a style choice.
General Training: cover all three bullet points
Every GT Task 1 prompt gives you three specific points to address (e.g. explain the situation, say what you want, suggest a solution). Missing even one caps your Task Achievement score regardless of how well-written the rest of the letter is.
Task 1 rewards a formula more than any other part of the exam — once you've internalized the structure for your test type, most of the work is choosing the right data or the right tone, not figuring out what to write next.