Use a consistent case

Case is how letters are capitalized. Mixing styles, such as "Add to Cart" next to "View profile", makes an interface look careless.

The common choices are:

• Sentence case: only the first word is capitalized, as in "Add to cart". Many products use it because it is easy to read.
• Title case: most words are capitalized, as in "Add to Cart".
• All caps: every letter is capitalized. Use it sparingly, because it is harder to read.

Pick one style for each kind of text, such as buttons or headings, and use it everywhere.