Similar to back stitch, running stitch is great for straight lines and outlines, only it's a dashed line. It's also great if you want to make something with a drawstring on it!
Here's how ya do it!
Bring needle up at A and re-insert at B. Pull through to the back of you work (photo one)
Bring needle back up at point C, leaving a gap between point B and point C, and re-insert at D (photo two)
Bring needle up at point E, leaving a gap between E and D, and re-insert at F (photo three)
Repeat as necessary