OTD for me was tax, title, processing fee, and dealer installed options.
Don't just accept all dealer fees. Ask the dealer what each fee is for, and if it sounds ridiculous, it probably is. There were a few fees that the dealer was trying to charge me and I refused to pay it for one reason or another. I ended up saving about $550 just by saying "NO".
When it comes to financing, I came into the dealership w/ a pre-approved loan from my credit union, and told them if they could beat the rate I was pre-approved for, I would finance through them. Of course they gave me a better rate so they could make some money on the car.
I hope these tips help you guys save some money!