Just imagine that you are drawing small circles in either direction and veer off just before you close the circle. Perhaps there is another type of stitch that you do find easier, that can be your signature stitch. Many of the good quilters do not worry about being too uniform, or it takes away from the design and doesn't look attractive. You could try doodling to fill in the space, and I am sure you will be pleasantly surprised. I know a lady who does very long, sausage like stipples and it looks fine because she is consistent.