Wow, the first shot Plumeria is just wonderful, nice backlight, excellent exposure and a nice composition.
The other shots are suffering from very harsh light and heavy contrast. Would be a case where fill flash would help balance the image for improved results. #3 is a cool flower, looks like a sea urchin of some type Hope to see more from you soon!
Karl Witt - Lack of flash, just had to work with Natural Light and they were taken middle of the day. I need to get better in working with the lighting and my PP skills.