Assuming you know the basics of On Page SEO (how to target your keyword properly in the title, URL, H1 tags, meta keywords, meta description, correct keyword density etc), here are a few extra things you can do not many of your competition will be doing (depending on how competitive the keyword is, of course):
First: embed a YouTube video on your page that's optimized in the title, description and tags for your keyword (the higher the quality, the better) and make sure someone in the video verbally speaks your target keyword at least twice – naturally. This is because Google now use voice recognition to analyze the spoken content of videos. If you can't find a suitable existing video, make one yourself. It doesn't have to be fancy as long as you mention the keyword twice. Also make sure to use your keyword in the video title, description and tags after you've uploaded it.
Second: upload some pictures to your page, name the pictures your target keyword (and some natural variations) and optimize the photo in the title, alternate description and meta description for the keyword (and variations), and make sure the destination URL (where the picture links to on your site) is set to your home page (or the page you're trying to get ranked).
Third: if you have comments enabled, disable your SPAM comment filter. Once you start getting some SPAM comments, remove the spammy names and change them to normal sounding names, kill the links they're trying to get and reword the comments to look more natural. In a few of the comments include your target keyword naturally.
And that's it! So simple, yet very rarely do I find websites doing all these things to target keywords On Page.