George's admonition to get out and feel is step one. And that requires someone, preferably more than one- who is worth going to meet and feel. Step two is probably more important. After you are satisfied that you have met someone with demonstrable skills. Ask to meet his students!!
I think that's a good start, Dan. I'd also suggest that people go meet some world-class expert like Li Tai Liang, Chen Xiao Wang, Chen Bing, etc., in order to get a feel of what someone with real skills *feels* like when they move, what they can do, etc. I would have named some Aikido guys in the above examples, but I frankly haven't felt any of them for a few years, so I'll defer until I'm exactly sure about who I'm recommending.
It's very easy to stop too soon with the first guy(s) that can "show you something good", kick your butt, who have great "lineage", etc., so the point I'd make is to keep looking around. That's how everyone does it.... always keep looking.
I have a couple of friends who studied on Taiwan for about 12 or so years with Hong Yi Xiang and others and based on their "credentials", etc., you'd think they would be someone you could go learn internal skills from. Unfortunately, they didn't really learn these skills because Hong had to save face with his martial-arts brothers on Taiwan so he loudly assured the members of the Taiwanese martial-arts association that he was not showing the good stuff to the foreigners. I learned this from a Chinese friend of mine who grew up on Taiwan. The point being..... you can't trust anyone to know everything they should know, so you need to keep looking for information from *all* sources. And constantly question yourself about what you know and believe. That's the hallmark of the real seekers.... and seekers always go further than "believers", IME.