I'd like to make keywords in the text more relevant for crawlers, and also to enhance some parts in the text to get an easy readability avoiding keywords dilution. I was thinking to do it this way:

    <p>I'd like <span class="bold">to make <strong>keywords</strong> in the text more relevant for crawlers</span> and also to enhance some parts in the text to get an easy readability. I was thinking to do it this way</p>

*p.s. the text in the span tag with bold class and the keyword in the strong tag will be displayed with the same style.*

Do you think it's a wise solution for an ideal mix of a good readability and a good SEO? If it is, did
 I write it correctly or do you suggest me to modify it?