You'll include them because they are descriptive of what you're selling. You'll include them because it will attract the readers’ attention and draw them to your store. That's not search engine optimization; it's just good marketing.
Lead, Don't Shove
The same applies when writing copy for your site. There's more than one reason to include keywords in your copy. The primary one is not the engines…it's your site visitors.
Strategic keyword placement helps guide your visitors to the information, products or services they are looking for. Don't shove keywords in everywhere you think you can possibly fit them. Instead, use keywords to lead your visitors in the right direction.
Even if there were no such thing as search engine optimization, your copy would almost certainly still contain keywords. It only makes sense to have keywords in the headline, so visitors will know what the page is about. Sub-heads? Sure thing!
People scan more than they read, so having keywords in sub-heads is a great idea. And in the body copy? You bet!
After all, it's pretty hard to sell desks without actually using the word "desk." Since there are school desks and computer desks and many other desks, you'll want to make it clear that your sale is for "office desks." That, too, only makes sense.
As you can see, keyword inclusion has been going on far longer than the Internet has existed. It's been an important part of copywriting since marketing was invented.
When you create a copywriting plan for your site pages, think through which keywords you should use and where the most effective places to position those keywords would be. Then develop your SEO copy with a goal of directing your visitors to the right information. When you do, you'll naturally optimize for the search engines at the same time.
Copy not getting results? Learn to write SEO copy that impresses the engines and your visitors. Be sure to also check out Karon’s report How To Increase Keyword Saturation (Without Destroying the Flow of Your Copy).