Mostly strangers do not offer sex and it can be difficult to proceed with sex when moat people are shy while saying hello to a stranger.
Greeting unknown people seems too hard a task when we set out for it as a start. However, you must be willing to let go of your prejudice before any interaction. Do not frame some unwarranted notion in your mind about the person you seek to interact with which could pose a barrier in your mind. However, some quick tips would be :
1. Begin with compliments, given effortlessly with an element of reality. Donot shower them with needless praise which seems unreal and patronising. It could be a tiny one nonetheless but definitely genuine.
2. A friendly handshake with a broad smile would serve your purpose.
3. Asking for help patiently and politely, expressing gratitude upon the same being rendered to you.
4.Giving a brief introduction of your own self and gently asking the other person (stranger) for his/her quick description.
5.Steering towards subtle hilarious conversations helps break the ice and set in the comfort level between two people talking to each other for the first time.
6. Not being condescending or avoiding expression of displeasure at their statements.
Overall, a broad smile, genuineness in your manner and an amiable body language combined with patience for hearing the other party out are the key elements for greeting unknown people.
After being friendly and known to a stranger you can tell them your desire of sex with them and then they can approve or deny according to their rules.
I hope it helps