Any print shop with an addressing machine calls itself a direct mail company these days. What most of them actually do is print postcards, slap an address on them, and call it mail. Letters - real letters, in envelopes, with letterhead and a reply device and a P.S. that does actual work - are a different product entirely. They require production capability that most local printers don’t have and copywriting discipline that most marketers skip.
That’s exactly why they still convert. In a mailbox full of postcards and catalogs, a letter in an envelope is the one thing that signals: this is personal, this is important, someone wrote this specifically for you. Whether that promise is real or manufactured, the response rates back it up consistently.
A postcard announces. A letter asks. For any campaign where the goal is a real action - a call, a donation, an appointment - the letter wins.
The Anatomy of a Letter That Works
Before the tips, it helps to understand which parts of a letter actually get read. Eye-tracking studies and decades of direct mail testing tell us the reading order is almost never linear:
Letter Reading Order · What Gets Seen First
P.S.
Read first - almost always. The P.S. is the most-read element of any letter. It gets scanned before the body, before the headline, before anything else. If your P.S. is weak, your letter starts with its weakest moment.
Headline
Second most-read. The Johnson Box (a headline above the salutation in a ruled box) or a bold opening line determines whether the letter gets read at all.
Salutation
“Dear [Name],” vs. “Dear Friend,” - personalized salutations lift response rates measurably. The eye goes here immediately after the headline.
First line
If the first sentence doesn’t create a reason to keep reading, most readers won’t. This is the single most important sentence in the body.
Subheads
Readers scan before they read. Subheadings that stand alone as selling points - not just labels - keep scanners engaged long enough to become readers.
Body
Read in full by a minority, but that minority is your most qualified audience. Write for them. Every paragraph earns the next one.
Reply device
The reply card, envelope, or response form. Gets examined early - people want to know what they’re being asked to do before they commit to reading.
The 12 Tips
01
Write to one person, not a crowd
The letter should read as if it were written specifically for the person holding it. Use “you” throughout. Avoid language that signals you’re addressing a list: “customers like you,” “people in your situation,” “many homeowners.” Those phrases remind the reader they’re on a list. Remove them.
Test: Read your draft aloud. Every time you feel like you’re addressing a crowd, rewrite that sentence to address one person.
02
Lead with a problem, not a product
Nobody opens a letter hoping to learn about your company. They open it hoping it’s relevant to something they care about. Start with the reader’s problem, fear, desire, or situation - not with who you are or what you sell. You earn the right to talk about your product by first demonstrating you understand their world.
03
Personalize more than just the name
A personalized name in the salutation lifts response. But deeper personalization lifts it more. Reference the recipient’s city, their industry, a recent purchase, a membership status - anything that proves the letter wasn’t written for everyone. Variable data printing makes this possible at scale without sacrificing production efficiency.
Research consistently shows: adding a name alone increases response rates by 135%. Adding relevant personalized context beyond the name lifts it further.
04
Make the first sentence impossible to ignore
The first sentence has one job: make the second sentence get read. It should be short, startling, or specific. “Most businesses in [City] are paying too much for [X].” “There’s a deadline most people don’t know about.” “I’m writing to you because you’re one of [X] people who qualify.” It should never be your company name, your history, or a generic greeting.
05
Use white space like a weapon
Dense paragraphs signal work. Short paragraphs - two or three sentences - signal readability. Indent your paragraphs or use line breaks between them. The letter should look like it’s easy to read before anyone reads a word. In a test between identical copy formatted tightly vs. with white space, white space wins on response rate almost every time.
06
Write subheadings that sell, not label
Weak subhead: “Our Services.” Strong subhead: “Why 340 businesses in your area switched to us last year.” The subhead must work as a standalone selling point for skimmers. If someone reads nothing but the headline, salutation, subheads, and P.S., they should have a complete understanding of your offer and why it matters to them.
07
The P.S. is your most valuable real estate
It gets read first. Use it. The P.S. should either restate the core offer with urgency, introduce a bonus or incentive, reinforce the guarantee, or drive the call to action. It should never be an afterthought like “P.S. Thanks for reading!” That wastes the highest-attention spot in your letter on zero selling content.
If you could only keep one sentence in the letter and had to cut everything else, keep the P.S.
08
One call to action, stated multiple times
Do not give people multiple things to do - call, or visit, or email, or fill out the card, or scan this QR code. Choose one primary action and make it impossible to miss. Then repeat it. State it clearly in the body, in the P.S., and on the reply device. Repetition is not redundancy in direct mail - it’s instruction.
09
Match the envelope to the message
The envelope is the first creative decision. A plain white #10 with a live stamp feels personal. A window envelope with a teaser line feels like an offer. A colored envelope stands out in a pile. The wrong envelope undermines the letter inside before it’s opened. The right envelope sets up the read. Don’t treat it as a packaging afterthought.
10
Include a reply device - even if your CTA is digital
A reply card or return envelope increases response even when most people respond online or by phone. It’s a tangible reminder of the ask that the recipient can set aside, carry to their desk, or pin to a board. The physical response artifact keeps your offer in the environment. Remove it and response rates typically drop - even among people who never use it.
11
Mail with your list, not against it
A brilliant letter mailed to the wrong list fails. A mediocre letter mailed to a
highly targeted list often works. If you’re mailing cold prospects, the offer has to be immediate and specific to their situation. If you’re mailing a house list, you can lean on the existing relationship. The copy, the tone, and the offer should all be calibrated to the audience - not generic enough to apply to anyone.
List targeting is responsible for roughly 40% of campaign performance. More than the copy, more than the format.
12
The second mailing outperforms the first
Most letter campaigns are abandoned after a single drop that doesn’t immediately overwhelm. That’s a mistake. A second mailing to the same list - three to six weeks later, with a slightly different message or a follow-up frame (“I wrote to you last month about...”) - almost always outperforms the first. The first mailing builds recognition; the second converts it. Budget for at least two drops before drawing conclusions.
Why Letters Require a Real Mailing House
Here’s the production reality: a letter campaign involves printing, folding, inserting into envelopes, applying a personalized address (and optionally a personalized letter body), metering or applying postage, sorting, bundling, and dropping at postal facilities. A local print shop that also does “mailing” typically handles the print half and subcontracts or skips the rest.
A printed sheet is not a mailed letter.
The distance between the two is exactly what a full-service mailing house covers.
At US Presort, letters are a core product - not a side service. We handle the full production chain: variable data printing for personalization, folding and inserting, permit management, presort at the carrier-route level for maximum postage savings, and USPS-certified drop-ship to postal facilities. We also work with non-profit rates for qualifying organizations, which makes letter campaigns economically viable at volume levels that would otherwise be prohibitive.
Before you commit budget, run your letter campaign through the ROI Calculator to model expected response and return. If you have a letter campaign in mind - a donor appeal, a sales letter, a customer reactivation series - talk to us. We’ve been running them since 2001.