A simple concept to make a button "better" is to shift it down by 1px when it's clicked. This is not a new concept, in fact Chris Coyer wrote about it all the way back in 2010.

"Better" is of course a subjective attribute. Typically, websites employ various ":active" states for buttons, such as:

• Darkening the button background color
• Adding a highlight border color
• Using the default 'outline' glow