Only give compliments you mean. Fake ones make your real ones worth less.

Praise works like currency, and currency can be printed into worthlessness. Hand out compliments you do not mean and people start hearing all your praise as manners, including the one sentence you meant on the day it mattered. A generous habit quietly destroys the thing it was trying to hand over.

Say fewer of them and make them specific. Name the actual thing: the pass nobody else saw, the paragraph that was better than the rest, the way they stayed calm with a rude customer. If nothing true comes to mind, saying nothing is a perfectly decent option.