Manual or Auto?

If you’re not happy in Manual mode, try Manual and Auto ISO so that the ISO adapts to suit the light. To shoot indoors with window light, use your widest aperture and go as slow as you can on the shutter speed (1/80 sec is probably the limit). To avoid shake, engage VR or stabilisation if your lens has it, ask your subject to keep still, brace the camera and fire shots in bursts.