Make your online content easier for people to read so they actually read it! This is really more of a design issue than a content issue, but it’s worth taking note of. The following information would be for on-page content for a website. This would be somewhat different for a print piece:
Normally a dark gray is a good choice on a website compared to black on white, which can be a little harsh at times. Go for dark text on a light background or light text on a dark background.
You would make the font big enough for people to actually read. Sometimes designers try to get too cute with making the font small. I agree it does look good because it can give some good white space, but I lean toward allowing people to easily read the content.
According to studies I’ve read in the past, sans serif is usually best for the web and serifed fonts are better for print content.
Leading is the space between the lines. I normally like to have at least 1.5 lines for online content.
Headlines & Subheads
I like to distinguish the headline and subheads with a different color, font, and size. This makes them stand out since sometimes the only things people will read are the titles and subtitles.
Use bold and italics to show emphasis and create a visually appealing document.
You want to have plenty of white to allow a person’s eyes to rest when reading the content. Sometimes clients will balk at the idea of having chunks of blank space but this is good to move a reader’s eye to what’s important.
Studies have shown people can more easily consume written content that’s as wide as a newspaper article. Somewhere between 500px and 600px is easiest on the eyes.
Keep paragraph length short. Use 1-4 sentences in a paragraph. Vary your paragraph length and don’t be afraid to include one-sentence paragraphs.