Users come in a few types. The ones that are most common are people who seek information about something and those who seek to purchase something. To appeal to both types of users, you have to keep your content rich in information that would be useful and valuable to them. Product descriptions, on page content, blog articles and everything else has to be written with correct information before you consider the addition of keywords.
Pictures communicate just as well as a written description. While it is unlikely that an image would provide all the information a user may need, high quality images can be effective when used with well written content. In addition, videos, infographics and diagrams are also of great help to convey your message to users.
Content stuffing is a heavily frowned upon 'SEO don't'. If you overdo the keywords in your content and place them in an unnatural manner, search engines will notice this and penalise you for that. The best approach would be to keep your content interesting and informative and then to work in a couple of keywords as naturally as possible. Maintaining the keyword density is also important. If you have trouble working in your keywords into written content, be sure to contact a professional SEO company or a well versed copywriter to do the job for you.
SEO is all about reputation. Poorly written content, even if it's posted somewhere outside your website, can have a negative impact on your website's reputation. Be sure to keep your social media updates, article directory uploads and other descriptions in excellent shape to avoid being flagged down from search engines. If you are obtaining a link from an article, a status update, a tweet or just about anything that is associated with your brand name, make sure that it is well within the above guidelines.