Have you tried brushing sideways, or torwards the toe or brushing the heel? These can make a drastic difference. Especially the heel. Have a few practice approaches first without the ball if you try this.
I'm not sure how old you are, but if your feet have stopped growing, save up for a good pair of shoes. Dexters, Dynrooz (Global 900 these days), Linds etc. They are the only part of you that touches the playing surface.