I've only been vaping consistently for less than 3 weeks, so I'm still sorting out how I feel vaping in public. I think it's a learning process - we all have different comfort levels about it. So far I've vaped in places that allow smoking, but the only non-smoking place I've vaped was a hotel room where no one saw me any way. Tonight I'm going to a non-smoking bar, and I've already contacted them and got the okay, but it really depends on how it goes while I'm there.
Someone already mentioned carrying ECF business cards - I will be toting some of those as well as some information sheets for anyone who is interested. As Dougiestyle said, it's also good to ask yourself some questions to cement your own feelings in your mind. That way, when people ask, you have answers that pertain to you, not just info recited from elsewhere. I think that's important because YOU are the only one that can say why you vape, what you get from it, and what you hope to get from it going forward. One of the biggest disconnects I'm finding as I talk to others is the WHY - they don't understand why we vape.
Good luck, and don't feel like you have to take on the world. If you aren't comfortable with confrontation, then don't force yourself. I'm very anti-confrontational myself, so I quietly look for opportunities to share info but I don't put myself out there where I'm going to get swooped in on. BUT, I also don't feel like I'm doing anything wrong so I'm not exactly hiding either. There's a "happy medium" for each of us. You just have to find yours.