It is a fact of life: being proactive is key to success. A man can't sit around and wait on luck to bring him anything worthwhile in life and that includes women! So unless we learn the vital skill of approaching women NOTHING will happen.
The first two elements of a successful approach are the most often overlooked. These elements are your attitude and body language. I will not go into the proper attitude here because it is a different topic all together. Body language is something worth mentioning briefly. Think about how you're standing, your tone, and facial expressions when you are talking to a stranger or acquaintance. Taking a similar approach with women is far better than what most guys do. DO NOT walk up behind or directly in front of women squared off face to face with her. This is confrontational and uncomfortable. Instead try facing the same direction and turning your head to talk to her. This allows you to stand closer and seem casual. Just this one tip will make a huge difference in your approaches.
Now your thinking: "I'm standing next to her, what do I say?" Again think about your tone of voice and facial expressions first. How would you ask a person you had no romantic interest in for the time? You are casual and confident, positioned as if you could walk away at any moment. This body language shows you are calm confident and not needy.
If you have done all the above, a simple question or observation about the situation or even a simple hi will be all the words you need to comfortably start a conversation with a women.
Now as mentioned before Successfully striking up a conversation with women is much more involved than what you say. Your body language is just as important! The types of openers you use work better for different situations and carry a different risk reward profile. There are also other elements like time constraints, context, and transitioning into conversation, and how to open without any kind of opener or line at all. So keep reading and learning through experience.