No response... Thanks for the help guys. Been a big help.
Ok. The white balance is all over the place.
In terms of underexposure from the least worst to the worst...3, 1, 2, 4
Your DOF is too shallow for #2 at the angle that you shot it at. It actually takes a lot of skill to effectively use an aperture of 1.8 when you are that close. It just doesn't work at all. In #4, you missed focus, probably because of your DOF.
I mean, really, what critique do you want? You set your ISO to 800, you put your camera on aperture priority and set it at 1.8. You used your camera like a P&S.
My advice, buy an SB700 or SB600. It will open up a lot of options, allow you to control the lighting, and won't force you to shoot with settings that are unmanagable.
FWIW, I've been busy with a newborn son, a toddler, Christmas, and work. I had opened this thread to give positive feedback. Your second post contributed to the tone of this reply. But anyway, now you know why you didn't get immediate feedback. Most people probably didn't want to be rude or were to busy living their lives to wait for you to post a thread.