First and most important rule: Get a fixed-rate mortgage. Whatever you do, do not fall for some salesperson's mumbo jumbo about how much you can afford. Get a mortgage that stays constant for 15 or 30 years.
Decided what you can afford and stick to it. If you tell the sales person you can afford a $200,000 house, I guarantee you the first thing he or she will do is show you $250,000 houses and tell you how much nicer it is. F--k that.
Sales commission is directly tied to the price of the house, so the more expensive the house, the more commission the sales person makes. The sales person has all the incentive in the world to upsell you.
You are in a buyer's market. Remember that. Everything is negotiable, especially price.
If you can, set aside a few thousand dollars for incidentals after you move in. You'll be amazed at how many trips you make to Home Depot for garden hoses, and shelf paper and closet organizers and drapes and, and, and, and ...
Make sure you know what comes with the house. Do the window coverings - drapes and blinds - stay? That alone can be $2,000 to $5,000 on top of the cost of the house.
Do you have kids? It's worth paying more to be in a primo school district instead of a crappy one.
When you walk through the house, make a list of stuff you'll need to replace right away and wish list for down the road. Put a pencil to those items and figure out what they'll cost.
You'll have to get a professional appraiser. Make sure everything the appraiser finds - from leaky faucets to a leaky roof - gets fixed before you buy.
The mortgage company is required to provide what's called a good-faith estimate of closing costs - what you'll have to pay for escrow, fees, etc. Within two to five days of closing, you'll be given an exact breakdown of much cash you'll need to bring to the closing.
If you get to the closing and they tell you, "Oh, we forgot to add $2000 for this and $900 for that," DON'T PAY IT. This is one of the most common trick mortgage companies will use to screw you. Once they give you the final breakdown of closing costs, they are legally bound to stick to it.
Don't fall so much in love with one house that you aren't willing to walk if you can't get the right deal. In this market, there are amazing deals on great houses from Maine to Southern California.
Also, your sales person should be able to provide you with detailed info on utility costs. They can vary greatly from house to house.
That should get you started.