It's important to find books that speak to your style. McKee has one opinion Blake Snyder another. There are lots of opinions and styles out there. Keep in mind that screenwriting has three components: story, structure, and format. Story is the what the underlying experience the reader/viewer has when seeing the film. The structure is more about the pacing and presentation of the material. The format is how structure and story are committed to paper so it can be used in production. You want a book which helps to address these three elements. At the moment, I can't think of any that do a good job. Many focus on one aspect or another--McKee on Story, Snyder on Structure and Trottier on Format. I'm not suggesting they are a golden trinity, but they are often quoted and well respected by others.
Trottier's Screenwriter's Bible is good for formatting questions. His other advice, to me, seems less direct and helpful. Drc's advice about reading screenplays is very important.
This last statement is what caught my eye and threw me. "... see how they fit in camera." There are two different types of scripts--spec(ulative) scripts and shooting scripts. Spec scripts do not include camera angles or directions. Shooting scripts--produced from purchased/optioned spec scripts--will often include notes from the director or DP about angles, shots, etc. If you are not shooting your own script, your concern is not how it looks on camera, per se. While a screenwriter must be writing with shooting in mind, ultimately that is the director's call how it is shot.
Most films are produced by writer/directors. The director writes his/her vision into their script. Any script by the Coen Brothers shows this unique fusion. I mention this because pulling up a script from the Internet that was done on spec will lack much of the shooting information. No "PAN of landscape" or "ZOOM IN on hand over gun", etc. Most of that is just suggested creatively by the writer: "A white castle sits in the background of a rustic village" or "The deputy's hand quivers over the holster at his side." The DP or director then decides how that description gets translated to the screen experience.
Not all stories make good movies. No one structure accomodates all stories. And unless you intend to shoot it yourself, using a standardized format is essential as it makes it easier for actors, crew and other professionals to work with your script. Reading, writing and revising are the only ways to hone your skills. Good luck!
