Not a bad start! If you post the settings for each shot, it'll be easier to instruct you.
The first two (and possibly the third) have issues with DOF (depth of field). Top-downs are tough. And all of the shots need white balance corrections. My camera is always set to auto white balance, but color correction is sometimes necessary and can be done in post processing. Gimp is a good free photo editor to use. Also, if you haven't read Jer's article, do so:
http://www.nano-reef.com/forums/index.php?showtopic=190521