It seems that copywriting is one of those things that people, who don't know how to do it, take for granted. It looks easy enough to do. On the other hand, if you try to write copy for yourself you'll fast learn that it's not as easy as it looked. It can be hard to write copy that will get the job done if you don't have the knowledge to write good copy. Most people don't have the time or energy to learn it, so they outsource it to the pros who know how to do it. But if you do that it's recommended to find the time to learn some fundamentals so at least you can get a good idea about the copy that's written for you.
There was a time when capitalizing all letters was acceptable when making a point. It wasn't interpreted as yelling, but now it is and is considered rude. However in copywriting, to make a strong point you would bold words, or use italics, or even underlining. Yet another approach is to use a different font color for those words. Another consideration is it's much harder to read words in all caps. Don't be afraid of formatting because it can help you get your point across easily and accurately.
You can even add humor if it's appropriate, but be careful that you don't use too much. Whether or not to use it just depends on the product and your market. One thing you can use humor for is to break the ice a little and that will help people to let down their guard. Humor has long been known as a great relaxer, so if properly used it will only help your sales message. It really depends on your market, so you have to judge between what's appropriate. Naturally, avoid trying too hard to be funny.
You can also insert headlines into the text to introduce a new concept. By placing a large, bold headline in the middle of your page, you can introduce the next section of the sales letter and give readers a preview of it. This is also a good way to reach readers who may be skimming your page before reading all of it. This is how most site viewers decide if they want to read the body of the page or if they want to click on to someone else's offer.
Selling has never been easy, no matter what it is you want people to buy. The best copywriters can make their work seem like it was easy to produce. Yet when you attempt to write your own copy, you will probably figure out just how much effort is involved in a good sales letter or ad. Copywriting is something that must be studied and practiced before you can master it. Don't get discouraged. One day you will find that you are a proficient copywriter!
