What are good button style options?

With buttons, when should you use a solid style attribute, and when outline?

A solid button is more prominent than an outline button. Use solid for the primary action that you would want the user to tap or click, as it'll draw their eye/attention. Best practice is having one main action only - style the rest of the accompanying buttons as outline, as not to compete with the main action.

Related tip: Also keep the primary action (solid button) on the right.