I know with AdSense , it adjusts it self with the content on your website to post ads with your site. My question is if you wanted a certain keyword to come up on the AdSense ad, would proper SEO help bring more ads to your keyword your looking for.
Yes, as long as theres ads for that keyword at the time, put it in your metas, obviously on page, dont overdo it though, if thats what your talking about.
if you want certrain keyword based ads, then you need to focus on on-page optimization based on that specific keyword. for example: editing the title and description tag, focusing on the keyword in each parapraph, etc. also, if a specific section of your page has more info involving the keyword, you can try section targeting as well
well, I guess there is no much relation between SEO and ad targeting, as the Adsense crawler does not evaluate he SEO score in your site first. Once your site/text/passage is related to a certain keyword, you will then get the targeted ads. If not, you can implement section targeting too. http://www.dagsensecodes.com/2006/11/impleneting-section-targeting-to-get.html
Create contents by optimizing the targeted keywords in it without overdoing and sure your ads displayed will be related to the targeted keywords