A few people have said be sure to research things thoroughly about the market and where you're buying. How is this done?
The short answer is to pick up a "buying a house for dummies" book. They won't leave much out.
A longer, biased, old fart answer is to do stuff like this: Get obsessed with the local real estate market for about 10 years. Don't let a day go by without seeing what comes on the market. Drive by and go in open houses. Have 40 million water cooler conversations about amortization and safe neighborhoods and earthquake retrofitting, etc. (This kept me distracted from a job I hated, until I figured out I wanted to go to med school.)
Okay the real list:
1. Find an MLS (multiple listing service) website for your area. The biggest local real estate firm is probably the best site. This lets you see what's for sale, how fast stuff sells, and it gets you going on vocabulary.
1a. Look at craigslist for your area. This will give you a very small subset of the houses for sale, but sometimes a totally different picture.
1b. Stop when you see a for sale sign. Steal a flyer. Get comfortable with the real estate agency names and figure out which ones are big and successful. Think about everything listed on the flyer (bedrooms, yard size) and be scared at the sale price.
2. Find city and county home sales records online, if they exist. This lets you look up "comps" (comparables) to houses that interest you.
3. See if zillow.com has details for your area yet. The information on this website is staggering, including satellite pictures, valuation trends, neighborhood sales history. Seriously great site.
4. Look at local police records about crime rates and maybe the sexual offender residency reports, things like that. See if there's a neighborhood breakdown. You can typically go meet with a cop to talk about what they know. Don't assume a neighborhood is safe because it has an elementary school or a playground.
5. If there are obvious neighborhoods you're looking at (close to school etc.) go see, go walk around, look for graffiti and abandoned cars and homeless teenagers, talk talk talk to people. If you're looking right before school resumes, you'll have no idea what the noise levels are going to be like; this stuff is why you have to talk to people.
Then there's the whole "how to get financing" topic that I don't enjoy so I'll let others take it on.
When you're looking at a house or condo, here are some good things to do:
1. Visit multiple times, morning and night, walk the neighborhood, talk to people. Ideally you would get a feel for how loud it is during morning/evening commute, during Friday/Saturday night party windows, and you might witness neighbor behavior that impresses or scares you. See how hard it is to get to school/work from there AT RUSH HOUR, and how hard it is to park.
2. Unless you're truly loaded, don't play the competition game. Be totally willing to walk away from a house you think you love. Don't buy with your heart, buy with your brain. Don't make an offer until you know what you're getting into, by paying for a good home inspection, walking through with cynical friends, talking to neighbors.
3. If you're looking at a condo, talk to other owners about assessments and upcoming large expenses. Ask to see the last couple years' worth of association meeting minutes. Don't just trust the realtor/owner/board president. Lots of condos are sold just as the association is about to levy a $x000 charge per unit for roof repair.
4. Unless you have the time to learn how to close a sale, you need a buyer's agent (the realtor that works "for you"). You can't use the seller's agent even if he/she is nice. Each is getting 3% of the sale price of the house, typically paid by the seller. This is a TON of money. You are not going to feel like they earned it, unless you're really lucky. My advice is to find the old guy with the cheap car who has owned rental properties in the town for 30 years and went to school with the seller's agent's dad and tries to talk you out of everything. Dump any agent who doesn't kiss your a.s.s like it's never been kissed.
Like I said, it's a lot of work, expensive, and it sucks to do it alone. Best of luck to you.