The first thing I do when switching from regular sewing to quilting is lengthen my stitch length. Take a picture of your settings before moving them and try reducing your top tension a bit first. If that doesn't help, try increasing your bobbin tension by turning the screw on the bobbin case in tiny increments. You can turn the settings back for regular sewing by reviewing your pictures after you are done quilting.
Balancing stitches with two different colours of thread is tricky. Trial and error on practice swatches is how I do it before working on my quilt.