If you’re using white text on a dark background, don’t do anything else with your site before fixing that. It makes for a miserable reading experience, and it will cut down dramatically on the links and shares you receive. Your text should feel like black text on a white background, even if the colors are actually very dark gray with very light gray. If you’re using one of those fancy textured backgrounds that’s taking forever to load — replace it. Site speed is an essential element of reader-friendly design. Bump your font size up. How big will depend on the typeface you choose, but 14 pt is a good starting point. Speaking of typeface (what most of us call font), choose readability before anything else. No matter how much you love the look of that fancy, hard-to-read font, replace it. Don’t use 20 different typefaces all over your site. Choose one for your headers/subheaders and one for your body text. Links should be underlined. Designers love to play with more attractive ways of indicating links — sadly, none of them is as clear to the reader as underlined text is. When you’re writing content, break it up into fairly short paragraphs. Avoid very wide or very narrow columns for your text: both are hard to read. Columns that are 450-550 pixels wide tend to work well (here’s an article explaining why).