brick stitch (also called long and short stitch) is a simple and easy fill stitch. you can use it to fill an area completely, or to make a line wider and bolder.
brick stitch starts with a foundation row of simple back stitch. the next row is just another row of back stitch, offset -- like bricks or subway tiles. then, repeat the rows to fill whatever shape you're stitching.
keep all of your stitches the same length EXCEPT for the stitches at the ends of each row. the end stitches will be either full length or half (long or short) to construct the brick pattern.