Wrap a series of buttons with .btn in .btn-group.

Instead of applying button sizing classes to every button in a group, just add .btn-group-{lg|sm} to each .btn-group, including each one when nesting multiple groups.

Create split button dropdowns with virtually the same markup as single button dropdowns, but with the addition of .dropdown-toggle-split for proper spacing around the dropdown caret.

Make a set of buttons appear vertically stacked rather than horizontally

Combine sets of button groups into button toolbars for more complex components. Use utility classes as needed to space out groups, buttons, and more.

Place a .btn-group within another .btn-group when you want dropdown menus mixed with a series of buttons.

Do more with buttons. Control button states or create groups of butons for more components like toolbars.

Add data-toggle="button" to toggle a button's active state. If you're pre-toggling a button, you must manually add the .active class to the <button>