Is there a way to remember the difference between gross and net?

Just remember the fact that "gross" is german (and also french) for "large"

therefore gross is "larger" than net.

so in the case of income for example...your gross income is "larger" than your net income (i.e. gross income is before tax).

in the case of a can of food, gross weight is "larger" than net weight (i.e. gross is weight of the food+tin+water...net weight is weight of just the food).