I don't have a tilt screen, so when I want to get right down into the weeds I'm more likely to lie down prone. Whether I do it standing up or lying down depends largely on what the subject is. Little flowers can be better down low. If you want to shoot a flower from above, obviously you must be above it. If you're aiming at a single flower it's different from aiming at a field of them.
I rarely use a tripod for this, as it's usually bright outdoors. Not sure what is meant by guessing at the composition. You always guess until you see the picture.