Your subjects are way to close to that background. You need a wide-ish aperture and about 2 meters for it to fall out of focus and thus hide the texture. This will also stop the shadows that you appear to have trouble with and stop the shots looking like they are taken in a passport booth.
Hope that helps you improve!
Ps. if you read back a few pages you’ll soon see why it’s often best to just bight your lip.