It takes a certain finesse to work a touchscreen. Here are some common operations you can perform by using your fingers on an Android tablet's touchscreen:

Action Description
Touch The simplest way to manipulate the touchscreen is to touch it. The touch operation is similar to a mouse click on a computer. Generally, you're touching an object, such as an icon or a control. A touch may also be referred to as a tap or press.
Double-tap Touch the screen twice in the same location. Double-tapping can be used to zoom in on an image or a map, but it can also zoom out. Because of the double-tap's dual nature, I recommend using the pinch or spread operation instead when you want to zoom.
Long-press A long-press occurs when you touch part of the screen and hold your finger down. Depending on what you're doing, a pop-up menu may appear or the item you're long-pressing may get "picked up" so that you can drag (move) it around. A long-press might also be referred to as touch and hold in some documentation. Moving an icon or another object is a long-press drag.
Swipe To swipe, you touch your finger on one spot and then drag your finger to another spot. Swipes can go up, down, left, or right, which moves the touchscreen content in the direction you swipe. A swipe can be fast or slow. It's also called a flick or slide.
Pinch A pinch involves two fingers, which start out separated and then are brought together. The effect is used to zoom out, to reduce the size of an image or to see more of a map.
Spread The opposite of pinch is spread. You start out with your fingers together and then spread them. The spread is used to zoom in, to enlarge an image or see more detail on a map.
Rotate A few apps let you rotate an image on the screen by touching it with two fingers and twisting them around a center point. If you have trouble with this operation, pretend that you're turning the dial on a safe.