Where to put the Camera
Don't just accept just any old shot. Rather than plonk the camera down and start shooting, think about depth, colour, and - most important - what you want the picture to say.
Do you want a high angle or a low angle instead of a shot from eye level? The low one will tend to make the chap look important, the high one makes him seem less so. The two together (sorry my pictures aren't good enough to demonstrate this!) can work well if you're shooting a drama and want one person to look important and the other submissive. Though usually there'll be something else in the action to motivate the high/low camera angles - perhaps the dominant character will be standing and the other one sitting. There are sometimes other good reasons, though, for shooting high or low.
Look at these two pictures. The one on the right is so much more pleasing (at least I hope you'll agree). Apart from the change of camera angle to include the building, the main improvement is the shift of the horizon from halfway up the frame to one third of the way up.
The Golden Mean
The ancient Greeks discovered and rationalised a thing called the golden mean; if you divide an area with a line into three-eights (near enough a third) and five eighths it looks most pleasing. It comes into play in all sorts of ways - the most obvious one is when you're shooting a person; the eyes (the centre of interest) will nearly always be one third of the way down the frame. There are always exceptions; an obvious one is (thinking about landscapes again) a picture including a lake or other large area of water. The artist might well put the horizon halfway up the picture to include the reflection of the tree or whatever. But look at where the tree is - probably one third of the way across the frame.
Here's another example of the 'horizon' being shifted. It's the join between the backdrop and the floor in this case, but the thinking is the same.
Choice of Lens Angle
A modern zoom lens has quite a variety of angles to choose from. It's tempting to leave the camera in place and zoom around to select the picture. Be careful, though, of shooting Close Ups on a wide angle. The distortion can look horrid. Though there are always exceptions - are you doing a horror story?
Here are two close-ups of a chap - the left one was shot on a fairly narrow angle lens; the other with the camera much nearer and using a wide angle lens. It exaggerates perspective and makes his nose look enormous. So be very careful with your choice of camera position versus lens angle - imagine Miss World given the same treatment as this man!
But a wide angle lens can be a very good friend in the right circumstances. On the left is the same man again: this time he's been shot on a wide angle lens from a slightly low camera position; it gives him a 'superior' feel - good for a drama about the arrogant boss of a company. And on the right is the same chap playing a different sort of role! Mass murderer instead of megalomaniac.