This is just me but....
-Taxi. Roughly 20% of the fare but a minimum of $5.00. (I drove a taxi part-time while I was in college so I have a soft spot for these guys. Nowdays, many of them own the car, pay the gas and work long hours just to make enough to pay the rent and feed the family. In the 'old days', when I drove, the cab company owned the car and gassed it up; the driver got a percentage of the total fares before tips so the driver didn't have to front costs like many do today. Sorry for the rant. )

-Hotel shuttle. $3.00 to $5.00 depending upon the distance to the hotel and how helpful and friendly the driver is.

-Luggage check. Usually $1.00 per bag but a minimum of $3.00. If the baggage handler has been especially helpful and/or friendly I usually bump it up a buck or two.

One other thing---some of these rates may vary. For instance, luggage check in DT S.F. will probably expect more than luggage check in DT Petaluma.

As I said, that's just me....