AIDA

The AIDA model of advertising is the simplest and also most powerful formula you'll ever find anywhere. It stands for Attention, Interest, Desire, Action.

Attention
The first thing your copy needs to do is grab the reader's attention. You achieve this with your headline. Your headline should immediately catch your readers' attention and offer a clear benefit for reading the rest of the copy. The headline should be about your readers - not about you.

Interest
The next thing the reader sees after reading your headline is the first line of your copy, this first line has to be strong enough, and compelling enough to get them to want to read the next line.

Desire
You need to convert your reader's interest into a strong desire for what you're offering. That's why most copy should be long, much longer than you think.

Action
Tell customers what to do, because if you don't... they like as not won't bother. "Buy my product! You must have them all!"