Of course everyone does things differently, but you're looking for ideas so here's my story about what we did with our recent vehicle purchase:
1. I drive everything. You may have already decided that you want to buy a Toyota 4Runner, but it really drives your decision home when you experience ALL of the competition (no pun intended). Besides, it's fun.
2. Find some nice comparable vehicle of a different make. American-made vehicles do very nicely, since they are usually priced much lower for comparible trim. For my '04 4Runner purchase, I used a Mercury Mountaineer premier edition (loaded to the hilt w/ V8). I did everything except sign the papers on the deal, worked him down to a decent price, then told him I wanted to take the vehicle overnight to make sure I was making the right decision. I've never had a dealer refuse to do this yet. Also, I told him to give me the details of the price we arrived at so that I could go over them. We we're at $30,500.00
3. Next, my wife and I drove the Mountaineer over to the Toyota dealership. When the salesperson approached, I told him "We're buying this Mountaineer, and we're just looking." Of course, he proceeds in telling us what a mistake we would be making, and I stop him short and say "I like 4Runners, but they are over-priced. Besides, my wife is in love with the Mountaineer, and it's HER vehicle, I'm just looking." Now my wife is not the best liar in the world, but she DOES know how to act angry pretty well, so she says things like "Why are we even here?" and "I thought we made a decision." When a woman acts ticked-off, no salesperson in his right mind is going to press the issue, at least, not to her! My wife then goes and sits in the Mountaineer. Then I say to the sales guy "I think I can talk her into a 4Runner, but the only way you're going to get her to even consider it is by giving me the same price for the same options as that Mountaineer," and I handed him the details and price from the other dealership and wrote my cell-phone # directly on the paper. I said "we were heading over to sign this deal right now, but I think I can talk my wife into hearing what you come up with. Better work fast though . . ."
Now obviously, they won't be able to match options AND price, but they offered as much as they could for as little as possible and hoped for the best. The results: we ended up paying about $75 over invoice for the SR5 we wanted, with only the options we cared about anyway.