[header] How to start a conversation with someone on the train, bus or subway [title] Make eye contact. [step] Making brief eye contact can show the person that you're interested and help you gauge whether they are interested in you. Glance at the person (don't stare) and try to hold their gaze for just a second or two. 
Notice how they respond to your eye contact. If they meet your gaze, it's likely positive.