I enjoy trimming my css to the bare bones. One way is via shorthand.
background:…; instead of “background-color”
border:0; instead of “none”
font-weight:100; instead of “normal”
background:#fff url(img_tree.png) 0 0 no-repeat; instead of “color, image, position, repeat”
color:#fff; instead of “#ffffff”
0; instead of “0px”
animation:blink normal 2s infinite ease-in-out; instead of “name, direction, duration, iteration-count, timing-function”
font:16px/1.6 bold italic Arial; instead of “size, line-height, weight, style, family”
Some off the top of my head. Do you have any more to contribute?