Avoiding Crossing The Creepy Line

First things first: I am not a stalker, creep, or as my daughter periodically used to call me if I complimented any of her teenage girlfriends, a "perv". That aside, I have a dilemma. And this post, by necessity, must take the form of mostly questions. Remember: I'm a man (despite the androgynous first name), friendly by natural temperament, and I walk a lot.

What are your recommended guidelines when, while walking on the street, I encounter a total stranger and wish to avoid being perceived as a stalker, creep or perv? Assume said stranger is a woman (any age) or child. For example: If eye contact is made, who should initiate a smile? How long should said smile last? How broad should said smile be, i.e. teeth or no teeth? If teeth, how many? Uppers? Lowers? Both? How long should total eye contact, with or without smile, last? Are words other than "hello" appropriate? Who initiates said "hello"? If said stranger reciprocates with words aside from hello, what is my maximum number of allowable words to say in return? What words are forbidden? 

I have many other questions, including allowances recommended for regional differences, special protocols involving teenagers of either sex etc., but I'll be pleased if anyone takes the time and starts with those above.