[header] How to get a girlfriend if you're ugly [title] Smile at girls. [step] Smiling makes you appear happier to other people, which in turn makes you more attractive. The act of smiling even makes you happier, so it's not just an act, because your brain releases neurotransmitters like dopamine and serotonin when you smile that make you feel good. 
[substeps] In addition, seeing a person smile is actually coded as a reward in other people's brains. When you smile at them, they feel rewarded.