Hm, I think I may have a somewhat different view of this than many others.
So, first off, I will say that I do dress to some extent to stand out and be memorable. This is partly to do with the fact that I am very introverted and do not have a "loud" or very charismatic personality. So I dress in part so that people will notice me. And yes it does get people to approach me, and ask me about my shoes or whatever. So it's a way to start concersations, break the ice, whatever.
But I don't think that most people find my style "approachable" in the typical sense. It's a bit weird and different and may be intimidating, I don't know. I wear stompy shoes a lot. I would guess typically approachable would be someone dressed more like the environmental norm.
I walk every day through a place that is swarming with tourists, many wanting directions or photos taken, and I rarely get approached for these things. My husband, for example, gets asked much more often. But a lot of this may be due to attitude. I usually walk fast and don't make eye contact, lol. Plus I have some mild RBF.
ETA: I'm also conscious of being a small, Asian woman. It does make me feel safer to dress or act in a less "approachable" way. Take that as you may.