@kaz - Nice first shots .
The first one, may be you could have focused more on the flower, crop it a little ?
Did you use flash there ? Personally I try to avoid flash, most of the times I don't like the results I get using it.
Nice bokeh on 2nd, It'd be much better if you has a subject in the foreground.
The other 2 are ok I guess, nothing really interesting.
But these are just my opinions since you asked for critique. I am no expert.
@sujoyp - Bird one is nice.
HDR is nice but a somewhat noisy. How many shots for it & what program ?
I once tried Photomatix but I kept on getting too much noise so I got rid of it.