If your camera is sufficiently sophisticated, think about depth of field.
A photo taken at a very small aperture produces a picture where both the main subject matter will be in focus but so will the background. This may not be such a good thing if the background is not very attractive such as a wire fence, a wall or even the weeds on the next plot. At an aperture like f2.8 or f4 the background will tend to blur out a little. This takes attention away from the background and onto the main subject. Depending on the ambient light levels this could mean tending towards a very high shutter speed and wide aperture.
But if your camera is digital, and you are unsure compensate by taking loads and loads, then just discard until you are left with a total gem.