When creating buttons in blocks, resist your urge to emulate Hemmingway, and don't try to produce a treatise in a teapot. Small fonts, especially when italicized, are much more difficult to read. If you can't be terse, don't use the button for the description.

Try not to be redundant. Having a description that says "Do XYZ Today!", followed immediately by a button that says "Do XYZ Today!" begins to look like it's not well thought-through. Find different ways to say things in both places. That makes things more intriguing to read, and improves the search engine scan because there are MORE terms to catch, not just repetition of the same text.

When you write a button title, it does not work to "include" it in the flow of prose. There is a big visual difference between the button itself and the surrounding prose, and trying to make the button text part of a sentence in the prose outside the button makes the reader do a double-take. It's confusing.

One example: recently a block was posted on the site that immediately followed the "Register to Vote" button. The block itself was titled "Register Your Outrage!", and that block contained two buttons, "Register Your Outrage Here!" and "Take The Patriot's Pledge". So, there were THREE voter registration titles in as many inches, and two buttons where the button text was so long that it did not fit well: the lettering rendered poorly, with inadequate spacing for visual clarity. "Patriot's" looked like "Patnot's". "Take" looked like "Tale".