I will throw this answer out there. Though it's almost the exact opposite of what your asking.
Embrace your inner snob
These days society tells us that we need to be pleasant and have lots of friends. That we can and should measure a person's (or even our own) happiness and success though the sheer quantity of friends we have.
Well they are wrong. Many successful people were thought of as rude, rough, and snobbish. Though harder to prove, I submit that you can be happier with 1 or 2 people you can have a deep personal friendship with then 100 - 200 people you have a "passing friendship" with.
Now your goal of being approachable is a good one, and I am not trying to say that you turtle up into a tight ball and never talk to someone that doesn't share the exact same interests as you. That's no way to grow your self, and that's also important for happiness. However, trying to please a large population of people, to get them to like you, or even to get them to not-dislike you, well that's never going to work out.
So I do not advocate trying to reach out on unwanted subjects, or to try to bear with it on subjects you don't like. Instead, embrace your snob and try to welcome others to your subjects. Like playing video games, organise a "lan party" (do people do that any more, seems not). Want to talk about letter spacing in fonts, invite co-workers to a seminar on the subject. Want to have a deep conversation about soil erosion at your favorite beach, then get a party together to do just that. You may not get many people showing up, but at least you're approachable.
An example, a porty-potty is always approachable. Doesn't mean I want to approach it. If you're approachable, bu no one wants to tag along, that's their problem.
The other side is that the opposite of snob really isn't approachable. I know many approachable snobs. And there is absolutely nothing wrong with not wanting to hang out with people you have nothing or little in common with.