One if the best ways I have found to “find” new preppers or create them is to start talking about natural disasters.

The floods in Bosnia/Serbia, Katrina/Sandy, work layoffs, droughts, pretty much anything but the .gov and such.

As soon as you start talking about nsa snooping, dictatorships and the like, you will lose them. Let them come to their own decisionsin their own time.

Starting from a position of advantage of sorts is a help. What I mean is its easier for someone who already is in a gardening club or home gardens to see the value of canning and putting food back. Same for someone who shoots, putting an extra box or two of ammo back (crate) against price increases.

Use the common sense approach, not paranoia and it works out much better. Talk of stocking the pantry and larder rather than stockpiling, start using older terms, non-antagonistic language.
Slowly let them come around, they may never come around fully but can still be a help.