If you are using a desk lamp as main light, try to use a tracing paper, or butter paper, or a piece of thin white cloth put between the light and subject, to act as a diffuser, do not use it to cover the lamp as the lamp generate heat, the light will get more softer if this diffuser sheet closer to the subject.
I not sure what you want to archiver on the background, so only offer you pointer for the lighting.
Btw, some of the pictures look a little too warm to me.
Hope this help.