Advancements in the ability to move water around would be very important for agriculture and sanitation. An understanding of pressure and the associated invention of pumps would therefore have a major impact.
Obviously, steam engines would revolutionize a society, although it took Western civilization centuries to realize that.
The discovery of lighter-than-air gases enables flight and improves communication.
The ability to produce electricity, which almost certainly also requires knowledge of magnetism, and the ability to store electrical potential.
Mathematical notation is very important, and it came later than you might think. The equal sign was invented in 1557.

Hmmm… try to find a copy of Deathworld 2 by Harry Harrison. It might serve up some inspiration for you.