I don't think there's any "one right way" to go about trying to show friends and family that the religion is both false and harmful. But I do think there are a couple of things we should keep in mind.
1.) The religion is a social network
If we are going to get someone out it would be helpful if they have friends and family outside of the organization to whom they could gravitate. Getting them to spend quality time with non-JWs may be the best thing we can do. Building relationships with people outside of the religion gives them not only a safety net - but also cements the notion that non-JWs can be good people too.
2.) The religion controls information
Putting "apostate" material in front of trapped friend or family member probably isn't a good idea. However, giving them the tools to do research on their own can be highly effective. For example, showing them something benign like a link to the interlinear Bible
or, if their into science, maybe an article on ancestry showing that humanity has been around much longer than 6,000 years
The point here isn't to pursue any one line of evidence. But rather to give them the tools to access information outside the JW bubble.
3.) It's best to ask simple questions - and follow up.
You don't have to get into the teachings of 607BC. It can be something as simple as "Why do animals suffer and die?"
Ask the question - let them answer. And then leave it alone. Wait until the next time you see them bring it up, "Hey, you know how I asked you about animal suffering and you said x, y, and z? Do you really think that's true?" And let them answer again. And then leave it alone.
We have to remember that it's not about winning any particular argument. Rather, it's about getting them to think outside of the JW box. To get them questioning their own beliefs.
. . .
Just some ideas I've been kicking around. I've had success getting two friends out - but they were kind of already on their own path if you know what I mean. Anyways, I'd love to hear what your guys think. Anything else you've found has been / might be effective?