Tipping is one of the trickiest parts of travelling. There's the question of how much, but also how to handle the whole thing graciously. An American woman has come up with something called the GratPack to try to help. It's a folder of a dozen envelopes that each say "A World of Thanks" on the front. The envelopes tear away from stubs, where you can record who you tipped, when and for how much. Inside the back cover, tipping guidelines are provided — for example, $2 to $6 U.S. per day is suggested for a tour director, $3.50 U.S. per day for a cruiseship stateroom attendant. The pack costs about $12 Cdn., plus $3 for shipping, from Grat-Z
Some sample tipping guidelines are provided on their webpage.