If you can't incorporate the keyword smoothly, that keyword is irrelevant to the site, and you're doing both the site and the Internet as a whole a disservice. You will gather more visits - and more negative attention as soon as visitors detect they were deceived. Legitimate business lose customers that way - the very reasonable train of thought is "if they cheat at SEO, how sure am I they won't cheat at the cash register, or at warranty service?" - in essence, wrong keywords mark a site as dodgy.
Write actual, real, meaningful content. Not empty marketing blurbs but valid, helpful, professional articles.
I'm no SEO expert, but I maintain one site in a rather competitive area. I suggested the owner to write a series of advices to customers, short articles blog-like, detailing advanced techniques, common errors, proper maintenance, misconceptions, "industry horror stories", and so on. The language he uses is his own - not a smooth marketing slimeball, but an honest craftman, master of the trade, who is not afraid to call things their real names, or snark at idiocy of people who e.g. find a way to silence operation of a naturally noisy mechanism, completely compromising its purpose (and endangering their own lives) in the process.
That is incorporated in the page right next to a clear price list, testimonials of high-profile customers, contact and all the traditional elements of such a page.
The articles not only show in-depth knowledge of the author, they are quoted and linked on multiple fora on that subject. Result? Google's #1 on search for [main keyword][location], above competitors who pay SEO firms for increasing positioning of their domains. Sometimes he falls to #3 or so - but that's always temporary. SEO tricks don't beat actual content.