sometimes it helps to actually use a pencil and draw your 1/4" stitching lines, then you know exactly where to stop (at the cross points) instead of stitching across them, this helps reduce the bulk, then you press in a circular pattern around the block...all seams going in the same direction. there are some good tutorials for pinwheels that you could look at pictures to clarify...once you get the hang of it they go pretty smooth.
practice :) also helps