x2 - I am shopping now actually for a new home. Looked at 4 tonight with my agent, found 1 that I might be interested in, and looking at 3 more tomorrow.
Have an agent that you can really trust to look out for your interests. That's harder than it sounds. You need to know, and I mean real know, your agent. I have met some really shady agents out there - completely unethical. I can tell you several that you do not want to be involved with. Mine is willing to go the extra mile to make certain that I do not offer more than I should.
Have a solid loan company working for you. I checked mortgage brokerages - all were too high. Best deal was with one of the car guys who is at BB&T and handles their mortgages. He had the best advice to save me money, and the best rates overall.
Be ready to walk away from any house. There are so many out there that you need to know your numbers based on the comps and walk away if the deal is not fully to your liking. Do not get in a rush to buy.
Short Sales can take a long time to close. Check with the bank to see what forecosures they currently have - they offer better deals on these to get them off their books.
Have at minimum 10% downpayment - 20% is better. 10% is a lot better rates than 3%-9%. 10% down is usually better than 5% down and paying down points.
Make certain that the seller pays the closing costs, but only ask for what you need, not more. If you ask for too much, the seller will keep what you don't use.
Be ready to cut your earnest money check at the time that you make the offer. You need that instantly accessible, and it is usually 1% of the offer.