Once people have decided to click through to your website pages, you need to have content on those pages to keep them engaged and to live up to the promise of the page title.
Your page content needs to cater to the wide variety of people who are likely to need to know more about whatever it is that your page is talking about.
Words count It may go against your instincts but, providing you're not boring your site visitors, you need lots of words on a page! Your website designer may well argue against that statement but, if they do, you need to question whether or not they really have your best interests at heart, at least with regard to search engine optimisation.
The reason that the words on your pages are important is actually split up into two main components.

• Search engines index words better than anything else
• Some visitors like to read rather than watch videos

You can test the first of these points the next time you perform a search.
Even if videos show up in the results.
The search engines take account of the words on website pages and the more "clues" they have to go on - usually in the form of more words - the more likely they are to get their deductions right.
Opinions vary as to the best length for a web page and the glib answer is that it should be as long as necessary.
In practice, I would suggest that you aim for a typical page size on your website to include somewhere between 300 and 2,000 words.
That's quite a big range but if a page needs to take more than a couple of thousand words to get its point across, it probably needs splitting.
Both Amazon and YouTube limit the descriptions you can use to 5,000 characters (including punctuation) which works out at around 500 words.
Both those sites are big enough to have done a lot of testing and they also surround your description with a lot of other content, so that's a good indication that you should aim for at least 500 words most of the time.
Eye candy helps Your website designer probably won't like the idea of using large blocks of text.
You can get over that partially by writing in short paragraphs - much like I'm doing in this article.
Images and videos also help break up the look of a page.
The images you use should be relevant - we're long past the kind of images that used to be used in University rag mags (the adverts that had a scantily clad lady with the headline "Sex" and the sub headline "Now that I've got your attention").
Instead, images should support the main text in your page and, if appropriate, can be infographics that help interpret complex information.
You can also use videos to supplement the content of your web pages.
Some people prefer to watch videos rather than read, so including a relevant video helps increase the potential audience for your pages.