Interesting set. WesternGuy gave you some solid advice that will really help you move up to the next step.
Pic #1, while you have the whole flower in the frame, it's dead center, which is not the most pleasing position. I would have also enlarged the flower somewhat to lessen the amount of the background visible. And while the background is OOF, the strong white/black vertical lines is very distracting, and thus competes with the flower for the viewers attention.
Pic #2 is a solid, macro image. Nicely exposed, and the color saturation is perfect on my monitor.
Pics #3 & 4 both suffer from the same exact short comings; flower dead center, too large for the frame as you cut off some petals, and parts of the flowers are not in focus. Behind the focus point generally works as it blends into the background, but before the focal point is much more difficult to pull off.
Over all, for your 1st efforts, you're making some very nice progress. Force yourself to use your LCD both before and after each exposure to really see what you have. Use the histogram. Re-take as necessary. Believe, I do this all the time, and re-shoot many images. I still bracket f stops as DOF is hard for me to really see on my 3 inch LCD.