One little detail that can help give you sharper photos with better more vibrant color is to jack your ISO on your camera down to just 100, in stead of 800 ISO the camera wants to do in 'Auto' setting. That will maximize the image quality your camera is able to produce. My Nikon D7000 also does that a lot when shooting in 'Auto'. A low ISO makes the sensor less sensitive in low light, so you may sacrifice focal depth with a wider aperture, or a slower shutter speed, unless you can get a lot more light on your subject.
I hope you're not put off by this. I just hate to see your lovely images not be all they can be with the equipment you have to work with. Keep up the good work. You are more creative than 99% of the other wanna-be shooters/models here on DA.