Give yourself time
You can't expect to produce an exceptional document overnight. Letter-writing is actually harder than resume-writing because you're starting with a clean slate. In resume-writing at least you have your background--which is definite--to work with. In letter writing, you start with nothing. Letters can be about anything. That's why they're so difficult.
I once took a class called "How to Market a Book." The class focused on writing query letters to publishers to get a book contract. The course lasted six weeks and met for two hours each week. I spent several hours per week on homework--staying up all night several nights--and the end product was a one-page sales letter to publishers. Lots of work for just one letter.
I mailed the letter to about 30 publishers and got 13 responses. No one bought the book, but one publisher did offer to publish it for royalties only (no advance), which I declined. That book was the forerunner of this one.
Writers often say, "I don't like writing, but I like having written." That's how many of us feel. Writing can be hard work. Don't take it lightly, and don't feel bad if you can't write a high-impact marketing letter in half an hour. Neither can professional copywriters! Writing is a profession, like rocket science. Don't expect to learn or perfect it overnight.
Don't copy someone else's letter
Take these letters as samples and modify them to fit yourself, but don't copy them verbatim(逐字地). I've found that people who copy someone else's letter seldom get a good response, regardless of how good the letter is. Be original.
It would be easy to take the letters in this collection and use them word-for-word. That would be quick, but probably not effective. Your letter has to be "you." It should sound like you, feel like you, read like you--because you have to follow it with a phone call, or answer questions about it.
So, don't send a really "hot," aggressive letter if you're introverted and laid-back. You'll have trouble following up on the letter and you may not come across well. Send a letter that mirrors your style--and only you can write that letter.
Get professional help
If you're a skilled writer, fine. The project may be easy for you. But if you're not, you may need help. Consider hiring a professional freelance writer(自由撰稿人) to help you compose and edit your letters, but not to do them for you.
Where can you begin to look? Call your local ad club for the names of direct mail freelance writers. Read the classifieds in Writer's Digest. Check the Yellow Pages under "Writers." Contact your local writers' guild. Check with local advertising and PR firms. They use lots of freelancers. Newspaper and magazine editors know writers too.