Thanks Fallenphoenix for the comments..you are right, they look a little underexposed. For all the shots, I was using the manual mode and learning the meaning of apertures and F/stops, etc.
I am now off to try some more shots and hopefully of some buildings.
In the meantime...here are some attempts at marco shooting:-
For macro focus, most of the time it is best to have the eyes or if those are too small, the head of the subject in focus. Try to frame your shot such that the background does not have any distracting elements, that will take the persons eye away from your subject. You might want to move the camera lower, higher etc. This is the advantage of the tilt/swivel LCD. For instance, image #2, you can try shooting from a lower angle, this might get less of the brown stalks that are currently in focus and which I find distracting.
You might want to try shooting butts with the long end of the lens, this way you can get them without scaring them away.
In terms of exposure, you might want to be careful about shot #1. The white patches on the wings are blown out. If metering is a pain, you can always lower the EV by 1/3 or more. Make sure the subject is exposed, since most of the time, you do not really care for the background.
BTW, I shoot almost all my macros in P mode. In terms of focusing, you can try locking the focus at one point, and move the camera towards/away from the subject for focusing.