How to Write Ad Copy That Converts: A Field Guide
A practical, step-by-step process for writing ad copy that sells, from research to final edit, with examples and checklists for Meta and ChatGPT ads.
Good ad copy is rarely the product of a flash of inspiration. It is the product of knowing exactly who you are talking to, what they want, and what would make them believe you can deliver it. The writing itself is the last ten percent.
This field guide covers the full process, in the order you should do it. It is written for people who run their own ads or brief someone who does, and it assumes you sell to consumers, creators or prosumers rather than to procurement teams.
Step 1: Know the buyer before you write a word
Most weak copy comes from writing for "everyone who might like the product." Strong copy picks one person in one situation.
Answer these four questions in plain sentences:
- Who is the buyer? Not a demographic. A situation. "Someone who just adopted a large dog and is replacing a chewed-up bed" is useful. "Women 25 to 44" is not.
- What do they want? The outcome, in their words.
- What stops them buying? Price, doubt, effort, timing, or loyalty to what they use now.
- What would convince them? The proof they would need to see.
Where do the answers come from? Your reviews, your support inbox, your post-purchase survey, and the questions people ask in forums and on ChatGPT. Our voice-of-customer research guide covers each source. If you want a starting draft, the customer persona generator produces one from your product page.
Step 2: Look at what already works
Before writing, spend 30 minutes in the Meta Ad Library looking at ads in your niche that have been running for 60 days or more. Long-running ads are usually profitable ones, because advertisers switch off losers.
You are not looking for copy to borrow. You are looking for patterns: which promises keep appearing, which proof types, which offers. That tells you which messages the market has already validated. The guide on starting from proven messages explains how to turn those patterns into a brief.
Step 3: Write the message before the copy
Write one sentence each for the promise, proof and offer. This is your message, and every version of the ad will express it.
- Promise: Your dog gets a bed it cannot shred.
- Proof: Ballistic nylon cover, chew-resistant seams, a 90-day chew warranty.
- Offer: Free shipping, and a free replacement cover if it fails in 90 days.
If you cannot fill in all three, you are not ready to write. The promise, proof, offer framework goes deeper on each part.
Step 4: Write ten hooks
The hook is the first line, or the first three seconds of a video. It decides whether anything else gets read. Write at least ten before choosing.
Hook patterns that tend to work:
- Call out the reader: "Big dog, shredded bed?"
- Name the problem: "Most dog beds last a month with a chewer."
- Lead with the result: "Six months later, the bed is still in one piece."
- Lead with the proof: "We tested this cover against a 90-pound shepherd."
- Ask the question they are asking: "Is there a dog bed that survives chewing?"
Pick the two or three strongest and test them. The ad hook generator is handy when you are stuck.
Step 5: Draft the body in a set order
Once the hook is set, the body follows the message. A reliable order:
- Hook (promise or problem)
- One or two lines of proof
- The offer and what to do next
Here is a hypothetical Meta primary text built from the message above:
Big dog, shredded bed? This one has a ballistic nylon cover and reinforced seams built for heavy chewers. If your dog gets through it in 90 days, we send a new cover free. Free shipping on every order.
About 200 characters. The hook and promise land within the first 125, which is roughly what shows before "See more" in the feed.
Step 6: Fit the copy to the channel
The message stays the same across channels. The length and framing change.
| Channel | Where the copy goes | Practical limits |
|---|---|---|
| Meta feed | Primary text, headline, description | ~125 chars visible in primary text, headline ~27–40, description ~25–30 recommended |
| ChatGPT ads | Headline and body in a chat card | Headline 3–50 chars, body up to ~100 chars |
| Landing page | Headline, subhead, proof sections, CTA | Must match the ad's promise |
Writing for ChatGPT ads specifically
ChatGPT ads appear below ChatGPT's answer, clearly labeled as sponsored, when the conversation matches your context hints. The person has just asked a question, so the best copy reads like a relevant next step, not an interruption.
A hypothetical chat card for the same dog bed:
- Headline (33 chars): A dog bed built for heavy chewers
- Body (90 chars): Ballistic nylon cover and reinforced seams. Free replacement cover if it fails in 90 days.
Notice what is missing: no "best," no exclamation marks, no claim that the ad knows anything about the person's conversation. OpenAI's ad policies prohibit unverifiable claims, fake urgency, ALL CAPS clickbait and implying the ad knows what the user said. Check lengths with the ad character counter.
Step 7: Edit hard
First drafts are long and vague. Editing makes them short and specific. Run every draft through these passes:
Cut
- Delete the first sentence if the second one is a better hook. It often is.
- Remove adjectives that do not prove anything: premium, amazing, revolutionary, innovative.
- Cut anything the reader would not miss.
Sharpen
- Replace vague words with specifics. "Lasts longer" becomes "comes with a 90-day chew warranty."
- Replace "we" with "you" where you can. The ad is about the reader.
- Use numbers only when you can prove them.
Check
- One idea. Does the ad make one promise?
- Believable. Is there at least one piece of proof?
- Clear action. Does the reader know what to do next?
- Compliant. No unproven claims, no fake reviews, no guaranteed outcomes for health or income, no competitor names.
- Matched. Does the landing page headline repeat the promise?
The ad copy grader scores a draft on clarity, specificity and structure if you want a second opinion.
Step 8: Write variations, then test
One ad is a guess. Three to five variations are a test. Change one thing at a time so you learn what mattered:
- Same message, different hooks
- Same hook, different proof
- Same copy, different offer framing
On Meta, give each variation enough budget to get a meaningful read before judging. On ChatGPT ads, where many accounts are still new and volumes can be lower, give tests more time rather than reacting to the first few days.
Common copy mistakes and fixes
| Mistake | Example | Fix |
|---|---|---|
| Feature dump | "Ballistic nylon, YKK zippers, 4-inch foam" | Lead with the outcome, use features as proof |
| Vague promise | "The bed your dog deserves" | "A bed your dog cannot shred" |
| No proof | "Built to last" | "90-day chew warranty" |
| Weak CTA | "Learn more" | "Pick your size, ships free" |
| Hype | "BEST DOG BED EVER!!!" | Specific claim, sentence case |
| Message mismatch | Ad says chew-proof, page says "luxury" | Make the page headline repeat the ad |
A copy brief template
Before you or anyone else writes, fill this in. It takes ten minutes and saves hours.
Product:
Buyer (situation, not demographic):
What they want (their words):
Main objection:
Promise (one sentence):
Proof (list, all verifiable):
Offer and CTA:
Channel and length limits:
Words or claims to avoid:
Landing page URL:How SecondWin writes ChatGPT ad copy
SecondWin follows this same process for ChatGPT ads, without the blank page. It reads your site to understand your product and buyer, studies the longest-running Meta ads in your niche to find the promise, proof and offer that keep selling, and identifies the questions your buyers ask ChatGPT. Then it writes original chat-card copy as answers to those questions, checks every ad against OpenAI's policies and its own rules, and launches it in your own ad account.
You can see the messages and sample ads it finds for your brand with a free site analysis. Plans and what each includes are on the pricing page.
FAQ
What is the most important part of ad copy?
The hook, because it decides whether the rest gets read. But a strong hook only works if it leads into a clear promise, believable proof and an offer. In practice, the most important work happens before writing: knowing exactly who the buyer is, what they want, and what would convince them. Copy built on that research usually beats clever copy built on guesses.
How long should ad copy be?
As long as it needs to be to carry the promise, proof and offer, and no longer. On Meta, put the essentials in the first 125 characters, since that is roughly what shows before "See more." On ChatGPT ads, the chat card limits you to about 50 characters of headline and 100 of body, so every word has to work.
Should I use emojis or all caps in ads?
Use them sparingly, if at all. All caps reads as shouting and is treated as clickbait under ChatGPT ad policies. Emojis can work in some Meta audiences but rarely add proof or clarity. Specific, plain language almost always does more than visual tricks. If you test them, test them as a single variable so you can see their real effect.
How do I write ad copy without making false claims?
Write only what you can show. Use specifics you can verify, such as materials, guarantees, process details and genuine reviews, instead of superlatives or invented statistics. Avoid guaranteed outcomes for health or income, before-and-after transformations, and fake urgency. Make sure your landing page backs up every claim in the ad, since reviewers and buyers both check.