On your camera and in your image editing software, the most helpful tool for assessing your exposure settings is the histogram. A histogram is a graph of the tonal values of an image, from black on the left to white on the right. The height of the graph at each point represents the relative number of pixels in the image with that particular tone or brightness level. The higher the graph, the more pixels there are of that particular tone.
On your camera, you can select to view either the luminance histogram, which displays the range of overall brightness levels from black to white, or the RGB channel histograms, which show the range of tones for each of the three colour channels.
In a colour channel histogram, the more the graph rises to the right-hand side of the histogram, the more saturated that colour will be in the image. Conversely, if the graph rises to the left of the histogram, the more muted that colour is in the image. For judging the exposure of your image, the overall luminance display is more useful, unless you are shooting a very vibrant and colourful subject where you could easily clip one or more of the colour channels even if the overall exposure looks satisfactory – more about this shortly.