Hold the camera very steady and press the shutter button rather than 'snapping' it. That is 'pressure' not 'movement'. There should be no camera movement in taking the photo. Choose a steady posture and if shooting in low light with a long shutter speed, rest the camera on something that does not move, e.g. the back of a chair, a rock or post, even leaning against a wall helps.
Focus is usually automatic but almost all cameras have a focus lock system. Most cameras will focus in the centre of the picture area. If the main subject of your photo is not in the centre - move to the subject, press the shutter button half way to lock in the focus - move (the camera) back to compose the photo and press the shutter button the rest of the way.
P mode offers some override functions - your instruction book will tell you what is available on your camera. (e.g.. under and over exposure).
A is for aperture preferred mode. A small aperture e.g. f16 offers near and far objects all in focus - OK in bright light. f5.6 or f8 concentrates on the subject chosen with blurred foreground or background. f4 or f2.8 (or larger if available) is good for very low light situations and has a small distance in sharp focus.
S mode is shutter speed preferred mode. Usually used for action photos where a fast shutter speed is required. A slow shutter speed can be chosen to blur all or part of the photo by choice e.g. a waterfall for the illusion of moving water.
Flash is automatic i.e. it fires the flash in low light and not in bright light. The flash light usually only carries up to 4 to 6 metres, therefore is only good for people and close-up objects. With backlight photos, people in the shade with a sunny background, switch the flash to " flash on " a flash symbol, usually after the auto when the flash button on the camera is pressed. "Flash off ". A flash symbol with a line through it, should be used for photos further away than the 6 metres of the light carry, e.g. a stadium or stage photo. The exposure may be slower so a steady camera is again essential.
Available to switch on or off on the camera. Used in poor light with flash where the person of people in your photo have enlarged eye pupil and reduce the incidence of red eye or retinal reflection. The flash fires 2 or 3 times to help reduce the large eye pupil size. Some cameras have a bright light to do the same job. Use 'red eye' only when taking people photos - otherwise switch it off.
Don't forget to look carefully in all parts of your photo - edges and corners especially, to avoid things like post and trees behind a subject's head or cutting off an important part of the subject. Leave a small space around the subject as all prints will be a fraction smaller than the total area.
All the above settings are suitable for the vast majority of photos taken, but more advanced photographers will use the manual settings, if available, for special effects.