Prism's suggestions right on the mark. Would add that the hand position is different when quilting than when sewing - even if just sewing straight lines with a walking foot.
When quilting, position each hand on either side of the needle. Palms down, with fingers splayed to get maximum "coverage". Keep slight pressure (not pulling exactly, just keeping taut) on the quilt top. At first you may need to stop frequently to reposition your hands, but with time you'll be able to "walk" your hands down as the quilt moves through the machine.
The purpose is to keep the quilt top taut (but not stretched) in a large area - ie the width and breadth of your splayed palms, as opposed to keeping it taut by placing your hands in the usual "sewing" position (one at the bottom feeding the fabric, and the other at the back - usually working with fingers alone).
If I see a small pucker start to develop near a quilted line - I'll lift my presser foot (with needle down) and "relax" the fabric away from the pucker with both of my splayed palms, then continue sewing.