Where would I start when making a first person shooter?

I'm trying to make a first person shooter and I don't know were to start. Any tips,hints,or sripts would be very helpful.

Look at the Unity tutorials. There is a "3-step tutorial covering the complete production of a first person shooter".

FPS Tutorial

Having bought the book, I can independently recommend Will Goldstone's book to be of great help for a 3D Shooter. While its not totally dedicated to the "shooter" aspect, it has enough general game development support to be really helpful.

Unity Game Development Essentials

Look At The Very Basic, Beginners Tutorial