Need suggestions for improvements

[corei5]

Hello, I'm new in photography but if guys in this forum could help me to improve my works I'd appreciate it.

please give suggestions on how to make it better, like settings to use like aperture and such, still using 18-55mm lens.

[daq7]

Last facial seems good, but you lost the saturation and a bit out of focus. The composition is nice though.

[hminx]

The third ones my favourite but you need to nail the eyes for sharpness. They all look a tad soft, so keep shooting and posting. What PP did you do with these ?