Complimenting someone on their hair, outfit, child, dog, etc., always works well. People LOVE to hear good things about themselves, and should respond positively. My daddy was the king of conversation starters... he could talk to anyone about anything. One thing that he taught me was to treat everyone you meet as if their heart is breaking... because it very well might be. If you approach everyone from a caring, friendly stance, the rest is easy.
In my opinion, a way to start a conversation can be through starting with a polite hallo and introduction of yourself. You can also ask a general question about something or make a comment then ask for what the other person thinks. Depending on where you are and the situation, choose what will work best. Be confident and smile to make the other person feel comfortable around you.