Hi. I'm a good looking guy

but I don't have much social confidence (I am confident but I guess you could say slightly socially ignorant) . I need some advice on my approach:
In a work or school environment
1. What are goods things to talk about when approaching a girl?
2.How to I avoid the 'friend zone'?
3.How and when do I show my interests?
Please help me with these and any other advice you think will help.
Thanks in advance and sorry if my english is poor.