During wedding photography, family photography, intimate photography, couples photography or even infant or newborn photography I'm always looking for lines.

About the only time I'm not looking for lines is headshot photography.  With headshots, you don't want a composition that's too busy.

This picture of my son was shot with a 50mm 1.8 (not the sharpest or best prime in my tool bag, but it did the job).  Notice all the lines here.  There's leading lines going from both sides of his head.  The pillow has lines zig zagging to his face. There's the line of his shoot that's pulling your attention to the right side of his face.  Then there's the lines in the background that's not completely in focus, but gives a theme to the overall picture.

This was a quick shot, but it turned out to be one of my favorites because of how the viewers attention goes straight to the subject.