The lighting's not too bad and you have some good expressions there, (Bill & Martha/Melissa) but yes you really need to think about the background and the aperture you use. Either a blank (set-up) background as in a formal portrait (and a wider aperture/greater distance between the subject and the background) or having the person in their natural environment (eg the dog could be nice but not with all that clutter in the background) Have a think about the composition too.

I didnt go past the first page but Lily and Jessica have some colour balance problems and are OOF.