The big thing I learned is patience. Be prepared to walk away from any house that is not what you want/doesn't feel right/isn't the right price etc.
We ended up in a great house that is pretty much exactly what we wanted because we walked away from several that were almost right. We even balked at the final minute on one, having made an offer, had it accepted almost, and we were going to sign the papers when I said, "No."
We found an awesome realtor. We used a mortgage broker. Both were really helpful.
Remember, you owe nobody as a buyer (until you sign the mortgage papers.) If you've been dealing with someone, and they are not giving you the service you think is reasonable, find someone better. The idea of interviewing realtors is a good one.
When you find the house you want, decide on the price you are willing to pay. Then bargain hard to get it for less (if that is reasonable to do in your market.) If you can't get it for what you believe it's worth then remember my first piece of advice.