My first advice is to pay with cash (check). I don't mean bring a large stash of $100s into the dealership. You have the most leverage this way. If you can't afford to pay with cash, then maybe you don't need that car. Anyway, that's a different topic.
The next thing I found to be really helpful is to be patient and realize if you don't get the deal you would like, there is always another car. After the long waits at the dealerships negotiating, I have moved to email transactions. My Fusion Sport purchase was decided via email. I went in and wrote a check and drove away. I didn't have to wait for the salesman to go talk to his manager, etc, etc, etc.
Another thing that is helpful is decide the bottom line of what you are willing to pay. The way I look at it is that I don't care if they want to call something a "docking fee," "tax," or whatever, I am willing to pay X dollars and they can write it up how they want to. Just talk walk out price.
Sounds like you have already purchased but perhaps this will help someone in the future.
The moon and tune wasn't a must but it happened to be in the car that I bought and I'm so glad now that I have it.