The first method I like to use it to use a sans serif font and a serif font one for heading and one for text. Then for links, buttons, I can do special decorations like underlining, italicize, bold, etc. which will help make things pop out to people. The second method is the one used in this blog. I used 2 sans serif fonts, and I mixed up the weights fonts sizes and the style of them and used them in different areas. So, my first font is Josefin Sans this is used for headers, sub headers, call to actions. You can make it bolder, a distinct color and the font size bigger because I want these to stand out to people. Then my second font, Lato is used for text, links, and certain call to actions. Links are italicized and an assorted color to pop out against the bodies of text. Finally, my third method is to just use one font and change the style of them. 

So, for example, my headers are going to be bold, bigger, and a different color, then to be able to use the same font and contrast them I make my text thin or light. I can make links, and call to actions standout with a color change, bolder/italicize, and capital letters.

Just a quick tip with any online project, assignment paper, work, presentation, anything that you make online. Use 16 pixels for text and nothing less. 16 pixels is a size that most people can read without any issues. Sub headers should be slightly bigger and then headers should be bigger than sub headers.