To not take advantage of an opportunity or situation to gain some benefit for oneself. Almost always used in the negative to convey the opposite, meaning that one is opportunistic. Did you really try to make a quick buck during the hurricane? You never miss a trick, do you? Even the best salesmen miss a trick once in a while. You'll get the next one.

To always be alert to any situation or opportunity from which one can benefit or of which one can take advantage. When you're hiring a PR consultant, you want someone who won't miss a trick. My father doesn't miss a trick—any chance to make a quick buck, and he'll be there.