One thing that most tourists will be shocked to notice is that Hollywood is not the magical, rich, celebrity hang-out that it is often thought of to be. It is surprisingly pretty run-down and not a safe place to be at night. Sorry to say that everybody... So take care with your bags, and get off the streets when it seems late.
If you are in L.A. I strongly recommend never ever to go out all by yourself at night, especially if you are a woman! This city is one of the most dangerous and violent in the world, so watch out!
Venice Beach is real nice during the day, but be aware that it is potentially very dangerous at night.