You need to see and be seen. Currently my favorite portable light for this is a Cygolite Metro 550 with the strobe over constant light. I can see by it and it's very eye-catching.

Also, as others have said, aim it down, I usually have the beam hit the road 40 or so feet in front of me.

Also some advice, if horns can scare you that badly, you need to get used to it. There are people who will honk at you just for being there.