Cross stitch
Backstitch outlines
Add crisp outlines to define shapes. Usually the last thing you stitch.
When to outline
Outlines add definition but they're optional. Small, simple motifs often look better without them. Portraits, animals, and anything with small text usually benefit from a single-strand backstitch around key shapes.
The stitch itself
Come up one square ahead of where you want the line to start, then go down at the start. Come back up two squares further along, and down at the end of the previous stitch. Each new stitch fills the gap behind the last.