I do them a lot. Here is the only piece of advice I can give you.
You must have a way to determine a clear yes and a clear no, and perhaps a maybe. If you read a yes/no like any other spread, you will not get a clear yes/no answer.
For example, I see people ask a yes/no and then throw a celtic cross, which is not intended to give a yes/no answer. So make sure whatever method you use (or come up with one of your own) gives a clear answer!
I don't think one card can give you a yes/no answer either. I would look more towards card placement, reversals. But pulling a card or two or three or ten is not going to give a clear yes/no.
Let your cards know what you are asking of them and they will oblige.
For the record, here's my yes/no: I pull three cards. Reversals indicate a no, while uprights indicate yes. I tend to count the middle card twice so there is the chance for a tie, which I take as "undetermined." I also read the cards as a regular three card, depending on my answer, to get a better sense of how I wish to proceed with the answer that I've gotten. If I get a no answer, they way to make it a yes is usually in those three cards.
Find a system that works for you. And keep trying them until you find the right one for you.