COVERAGE
How much coverage (angles and types of shots) you shoot depends on your budget. However, you need to shoot certain angles and get in the necessary number of shots for each scene, to be able to make your movie viewable, no matter how small your budget.
Shooting a long shot, medium shots and close-ups for every scene should be second nature to the way you work. Sometimes you can get away with one shot in doing certain scenes, but these are exceptions. If you're out of money, out of time or both, and all you can hope for is one shot, all right, I feel for you. I've been there!
But coverage is important for good results in the editing room, and your relationship to your editor, especially if it's yourself. If you have directed a film with poor coverage, you'll be banging your head on the wall. I know one director who bounces shots off the walls when he can't find a shot with the right coverage. A hundred feet of film on a core ricocheting off the walls of a small editing room is a dangerous thing! No film maker wants to compromise a sequence, and cutting your way around a mistake in shooting is a harrowing experience. I know some film makers who can't finish their movies because they don't have proper coverage. Sometimes you can't go back and redo something!
If you have prime lenses and you know how to use them, you'll automatically have good coverage. If you're starting out and you're unlucky enough to have allowed a zoom lens to be used as the main lens, you'll most likely have a plethora of uncutable scenes.
There are some intrepid film makers, although this is very rare, that rely on one lens to shoot their entire movie. They say that it produces a more natural way of seeing! Okay, I won't argue the point, but you do have to be extra careful to vary the angle and size of your subject so that you can cut! Also, the use of the dolly is difficult and limiting for the editor. Most of the time it's impossible to cut into a dolly shot. Keep dolly shots to a minimum. Use them only when effective. They take a long time to set up, too.
The natural way to shoot a scene is to shoot a master, a long shot, establishing the content, action and dialogue of a scene. Then you should shoot a medium shot or two, covering most of the important parts of the master. Then you do over-the-shoulders of your actors doing their dialogue in its entirety. Finally you shoot the close-ups of the climaxes and resolutions of the scene.
This is good coverage, but not comprehensive. If your budget is $100,000 to $150,000 this is all you can afford to do.
If your budget is below $100,000 and you're shooting 35mm, you should shoot the beginning and end of your master shot only. Go to over-the-shoulders immediately and cover your scene entirely in these shots. Then, especially if you've been lucky and you haven't done too many takes, you can shoot a few close-ups of each actor doing the final climactic bit of dialogue in the scene.
If your budget is over $150,000 you can shoot some additional types of shots. You can do dolly shots or crane shots. You can do fancy shots, if your schedule allows it!
If your budget is over $500,000 you can shoot full coverage. You can shoot a complete master and do several takes, until you have a fairly good master, correct in every essential detail, but not necessarily perfect. (If you're wondering when you can go for perfect masters and get away with it, I'll tell you: when it's not your money and when the budget is over $30,000,000 in the US, $15,000,000 in Europe or $7,000,000 elsewhere in the world.)
You also get to shoot dolly shots, crane shots, extensive helicopter shots (with Tyler mounts) and extra, highly creative coverage, such as multiple POV-type shots. Later, you can play editorially with a lot of the psychological aspects of shots and how they can be juxtaposed to produce different and ultimately insightful and cinematically compelling entertainment.
You say, "You should always do creative stuff, otherwise why are you making movies?" No, you make movies because you have to, because you're a film maker!