How to negotiate and get the best deal possible.

I noticed on the last e36 deals Tommy seemed to negotiate his deals before he ever went out to pickup the cars.

I'm not buying tons of stuff but I usually do the opposite. I generally find something and try to talk to the owner only as much as I need to before showing up with the cash to negotiate. I like to make it painfully obvious I'm not wasting anyone's time.

What do you guys have to say? Do you try to negotiate beforehand?

As a seller I avoid the internet tire kickers and sending offers beforehand is a red flag for me.