Make sure you're reading the "tips and notes". A lot of that is covered there.
Just to add to this excellent response, this is one thing that helped me appreciate the important of the two words:
Glaso de vino = a glass made out of wine (impossible).
Glaso da vino = a glass full of wine.
For the most part:
Da: a quantity
De: possession, affiliation, anything that isn't a quantity