Chris Lake suggests creating "1% clubs" of your customers -- segmenting them by value or engagement. "Monitor these groups, treat them differently, experiment, and learn from them," he writes.
For example, figure out the 1% most engaged ("useful for product development, crowdsourcing and cheerleading") and the 1% most unprofitable Then there's the 1% most price insensitive: "not necessarily the most valuable, or the most frequent buyers, but those customers who think nothing of splashing out on the best products. Segment these customers. Create dedicated marketing campaigns for them. Try to figure out how to make them purchase more often."