Striking a conversation

Before I forget...

Was walking alone back home. My house is ensconced in this little enclave of a park which is far yet not too far away from the hustling town centre of Clementi. Drawback for the beautiful scenery that I wake up to (similar to my room in Hall 11) is the need to spend about 10 minutes to walk in from the Nan Hua bus stop - now it is so easy thanks to the newly built road.

And there is this another person, without earphones sharing the same luxury as me of walking the same stretch of road.

And this random thought came to my mind, should I just strike up a conversation with the person?

I thought of the youtube video, about how 2 strangers in a ball pit would just start talking to each other.

And I start to wonder:
Do strangers need to have something in common first just to talk? In the video case they end up in a ball pit together. Will walking on the same road be counted as "something in common"?
Should I wait till the person finish using the phone? What if the person was on earphones (lucky the said person was not), should I even think of striking a conversation?
Should I have to mince my words would I probably sound too cautious? If I am too callous would I turn the person off? 
What topics can be brought up to sustain a good conversation? Would I sound too stalkerish? Or what if I touch taboo topics?

And what if the person is a he? Or a she? Would that change anything?

Something in me just feel like striking up random conversations with strangers. I think it is really fun to just start talking to random strangers about random things, because you can probably say more uninhibited things, and if you don't wish to declare anything you can simply say "it's personal" and the person would not judge you for not trusting him/her.

In the end, I walked back home singing to myself, because she was using the phone all the way.