Like some others, I use a small spoon.

Rocky

Funny you should ask. I've grappled with this issue lately since buying a new grinder. I have developed a technique of quickly flicking a spoon (a black plastic tablespoon I got somewhere for coffee beans). The grinder dispenses a fluffy mound of coffee in the center of the basket. If I quickly flick just the edge of the spoon I can take off a fraction of a gram without disrupting the rest of the coffee mound.

demitasse spoon but a .3 gram difference is not much. Depending on the accuracy of your scale that may be within the tolerance range of its measurement.