Click here. Buy now. Free trial offer. The world of advertising is full of short and snappy copy promising instant gratification. After all, most prospects simply don't have time to read thoroughly. They skim. They glance. But if you're betting they'll wade through long paragraphs of narrative copy, it's time to adjust your expectations. Your copywriting must be clear, compelling and to the point.

These days, the best copy is served a la carte, allowing readers to sample one message here, taste another message there. Which leads us to the most important rule in writing copy that sells: Make it "digestible." Rely on headlines, subheads, captions and bullet points--short snippets of copy with key nuggets. Long blocks of copy tend to overwhelm readers. If they snooze, you lose.

Here are five easy rules for writing copy for skimmers, scanners and at-a-glancers:

1. Match your copy to your visual (photo or illustration). Virtually all of us look before we read. If prospects see an interesting photograph, you've caught their eye long enough to at least coax them toward a corresponding headline or subhead. The message in your headline should always be the most important, preferably the key benefit of your product or service. If you use smaller inset photos, add short captions beneath them. Mix it up by italicizing the font in the caption; this essentially "tricks" the eye into seeing something different than more narrative copy. Try to embed a key message or two in the caption. Whatever you do, though, keep the copy block short.

2. Display your strongest message "above the fold." Prioritizing your messages may be one of the most challenging aspects of writing copy for your business. That's because you probably know your product or service inside and out and have so much to say. Just keep in mind that most consumers will only remember one thing at best about your product after reading your ad or e-mail. In fact, if you can get them to recall one benefit or feature and connect it to your specific brand, you've hit a home run.

So make sure you carry that main message in a headline and reinforce it throughout the rest of the ad. Also make sure to use your strongest pull in the subject line of e-mail campaigns and above the fold thereafter. (For example, online prospects should never have to scroll down on their browser to get to the meat of your message.)

3. White space makes your message stand out. It's a mistake to cram all sorts of information in your ad just because "there's room." Actually, there's not room. If a prospect's eyes are overwhelmed by large amounts of copy with nowhere to rest, nothing in your ad will get read. Most clients I've worked with in the advertising business constantly fight their tendency to overdo the copy, so be vigilant. Try to critique your promotional piece from a holistic view: If it looks too crowded, start editing.

4. Add a strong call to action at least twice. Like bookmarks, a strong and concise call to buy should be placed early in your promotional piece, as well as near the end. Be clear in how customers should contact you and always give your website address if you have one.

5. Focus on benefits, not just features. You've heard it before, but it bears repeating: People buy the sizzle, not the steak. Features are only a means to an end. What do the features of your product mean to the lives of your consumers? Will they be happier, healthier or have more leisure time? The main exception to this rule is with extremely technical audiences, who tend to be thorough readers anyway.

Finally, keep your sentences short and your style breezy, so your writing is easy to read and skim. When it comes to advertising copy, less is usually more.