Buying a Used Car...

I'll doubt I'll ever buy a new car ever again!  A 2-yr-old car with under 20,000 miles is practically new and will be easily 20% less than the price of the same car new.

*  Know what you're looking for ad how much to expect to pay.  You have to know how much a vehicle is truly worth!  Don't start with the sticker or what a dealer/seller says.
*  GET A CARFAX REPORT!!!  Dealers will pick up cars at auction and they may be off a salvage title.  Once a car goes through auction, the history is gone.  A CARFAX report will at least tell you if the vehicle was declared totalled at some point and then put back into circulation.
*  Be patient and wait for the opportunity to present itself!  Don't be afraid to walk away from a car and have it sold to someone else willign to pay more.  If it's not meant to be, it's not meant to be.
*  Dealerships are out to make money and they will typically sell at higher prices.  But you can find deals.
*  Ask to deal with the salesperson with the lowest numbers.  The person on the bottom of the "big board".  They need the sale so much more just to keep their job.
*  End of the month is the best time in dealerships.  They try to make their numbers and will cram at the end of every month.
*  But be willing to look for mistakes in dealership pricing.  I bought my wife a 2-yr-old '02 Honda Odyssey EX-Nav with 19k miles, worth $29,500 for $17,200 (less $4,500 trade-in on her old Camry) because the dealership listed the car on the Internet wrong for $19,500.  They tried to run some BS story about it being a mistake, but you want to know three things?  They can't legally kick you out once you declare interest in the car (don't walk outside!).  They can't sell you the vehicle for higher than the advertised price.  And they can't NOT sell you the car when all is said and done.  It may take you 11 hours in the dealership like it did me.  You may get cursed at by the owner who finally gave it to me at trade-in cost ($17,200) and of course I already got the $4,500 trade-in in writing.  And you should remember to bring food and a book because it could be a long wait.  But in the end, was it worth saving $12,300 ($1,118 per hour of my time)?  HALE YES!!!!  Sometimes these things do fall into your lap.
*  Consider hitting up your elderly parents and parent's friends.  My '98 Acura CL I bought from a friend of my moms.  5 years old with... 13k MILES!  She drove it to the beauty parlor and that's it.  Mint condition and when she asked, "how about a price?  Shouldn't we negotiate on a price?"  I responded, "Honey, you pick a price and I'll pay it."  "Well, the KBB value says it's worth $15,500.  Would fifteen thousand be OK with you?"  15 grand for an Acura with 13 thousand miles?!  Are you freakin' kidding me?!  These old, rich, classy people tend to take their car back to the dealer every month and give them a check to, "do whatever it is you need to do to the car."  So they're perfectly maintained.
*  If buying anything from other than a dealer with warranty (except if it's a creampuff like my Acura) get it fully inspected by an independent mechanic.
*  I would consider a dealer and pop in and out 3-4 times looking at the same car.  If it stays on the lot that long, they'll want to move it and will negotiate even further.
*  If you own a home, consider financing the car off your Home Equity Line.  The interest is tax deductable and the interest rate will be much lower than a bank used car loan.
*  Oh and...  BE PATIENT!

Good Luck!

I've never bought a new car, I've always bought used. I've never bought one from a dealer though, only privately. Actually I've only owned 3 cars, but my SO has owned lots, all bought privately too. In most cases we've sold them for approximately the same price we've paid for them, sometimes a little more, sometimes a little less, so if I ever buy a car again, I'd probably go the used private route.

If by "doing well" do I end up buying a car that I drive for years and years and years?  Yup.  If "doing well" means getting the car for less than anybody else, that's hard to say and really irrelevant. 

Purchasing a car (new or used) is a LOCAL transaction.  They have a car, you have money.  It all comes down to whether there is a mutually agreeable transaction price (in which case you exchange money for car) or not (in which case you keep your money, they keep their car).  Some people like the "deal" and won't buy a car unless they've spend hours researching, haggling, etc. because they like the emotional satisfaction of feeling like they got a better "deal" than anybody else would have gotten.  Others (like me) are more of the cut-to-the-chase and are OK paying a couple hundred bucks more to be done in an hour instead of a day/week.  Which type are you?  Sounds like you want to be in the "deal" camp but lack the experience (which suggests that isn't really your temprament, otherwise you could easily transfer the deal-making skills to this purchase). 

Sounds like you have time on your side (you've got the rest of the year, possibly longer).  How about vehicle flexibility?  Do you need 4-wheels and a box or are you looking for a medium-blue 2008 Accord EX with grey leather interior, no more than 22,000 miles, and a specific set of options?  The more flexible you can be, the more freedom you have to walk away from *a specific transaction* and that gives you leverage during negotiations.  That's really the key.  Are you ready to walk out if you're not making progress towards a mutually agreeable transaction price? 

What does the dealership have on their side?  They're familiar with the business and they do transactions all the time.  They have to guess what the future holds if they don't sell the car to you.  Most car salespeople have the "deal" temprament or they wouldn't be in that line of work and they're usually reasonably good at it or they won't stay in business. 

Some dealerships will search out a car for you.  Some may even work with you to buy a car at auction for you.  The more specialized the request, the tighter they'll want to nail you down on purchasing it before putting their money at risk.  If you're willing to buy any 2008 Accord EX with 20-25K miles and a minimum set of major options for $18,500, they can find one at auction for you.  It doesn't matter whether the car they find cost them $16,000 and they made $2,500 or if they got it for $13,000 and made $5,500, you got the deal you wanted (2008 Accord EX for $18,500).  You could offer $1000 over "cost" up to $18,500 for the car, but expect to get one that cost them $17,500 rather than the $13,000 one for $14,000 (they can put that one on their lot at $17,995 and expect a lot more profit). 

Treat the salesperson with respect. 
Walk out if the salesperson doesn't want to treat you with respect.
(Friendliness =/= respect). 

When you're happy with the transaction price, close the deal and don't worry how much profit the dealer makes or whether someone else could have gotten a better deal. 

The one piece of advise I haven't seen yet is to be prepared to walk away from a car you really like without buying it.

If you do your homework you should know roughly what you should pay for the vehicle.  Don't spend more than what you've budgeted.  It's too easy to find a car that you really like, but is more expensive than you planned to pay.  As hard as it is, walk away!  It might get the salesperson to reduce the price more, but that really isn't the purpose of walking away.  If you're not in a hurry, you'll eventually find the car you want that is within your budget.

Brian