Source: Adapted from publicly available forum Q&A on https://www.ieltsbuddy.com/. This is an original, condensed summary — not a copy of their site.

None of this is about technique — it's about the small physical/formatting anxieties that genuinely derail candidates mid-exam on the paper-based test. These are real questions test-takers have asked, with the practical answer to each. If you're taking the computer-delivered test, most of this doesn't apply to you.

Worry Straight answer
Can I write in block capitals the whole time? Yes, nothing in the marking penalizes it — but it's slower to write, so it's not recommended.
Does my essay need a title? No. Just start writing your paragraphs.
Do I have to leave a blank line between paragraphs? Not required for scoring, but strongly recommended. What matters is that the examiner can see a new paragraph has started. If your last paragraph runs to the end of a line and the next one isn't indented or spaced, it may not read as a new paragraph — and unclear or missing paragraphing can drop your Coherence and Cohesion score to a band 4–5. A blank line or a clear indent removes all doubt.
Do I need margins or double-spacing? No. Write on every line.
Can I cross out or erase words/paragraphs? Yes, freely. The examiner simply ignores anything crossed out. A visible gap from an erased word isn't penalized either. Don't overdo it to the point the page looks chaotic, but a crossed-out paragraph you decide to redo is completely fine.
Can I use American spelling instead of British? Yes — either is accepted, per the British Council's own guidance. Just be consistent; don't mix "colour" and "color" in the same essay.
Can I write a first draft, then copy it out neatly? No — there isn't time. You get 20 minutes for Task 1 and 40 for Task 2, and that has to cover reading the question, brainstorming, planning, and writing. Spend your prep time on a short plan (on the question sheet itself), not a full draft.
Can I make rough notes? Yes, on the question paper — you're not given separate scratch paper. The question paper isn't seen by the examiner, so anything you jot there is fine and stays private.
Can I get extra paper if I run out? Yes, it's provided on request if your essay runs longer than the sheets you're given.
I wrote Task 1 and Task 2 on the wrong answer sheets — am I penalized? No. This happens occasionally; the sheets get relabeled/reordered before marking so the examiner reads the right one against the right task. It will still be marked normally.
I left a stray plan, a guideline number, or scratch marks on my actual answer sheet — will that count against me or be read as part of the essay? No, these get ignored. That said, try to keep any planning off the final answer sheet where you can — a plan clearly separated from your essay is safest.

The one item on this list that genuinely matters for your score: paragraphing that isn't visually clear. Everything else here — capitals, spacing, spelling variant, crossing out, wrong sheet — is a non-issue. Don't spend exam-day anxiety on any of them. Spend it on making sure a reader can instantly tell where each paragraph starts and ends.