When crimping, position the crimp tool so that the part that pokes into the connector is in the middle of the barrel that surrounds the wire. As previously mentioned, the insulation sleeve on that connector covers the barrel, and then some more over the wire. Most likely the barrel is where the insulation is of the smaller diameter. Center the crimp on that smaller diamater part and you should be fine.
Perhaps you already know this, but....
Before crimping, look at the barrel of the connector. You should see that it's just a flat piece of metal that has been rolled to make a circle. Thus, there is a seam. You want the part of the crimp tool that 'pokes' into the barrel of the connector to poke into the side OPPOSITE the seam. Looking at the pic that kaytrim quoted, the 'poke' should be on the back (which if that connector is crimped, then it is correct.) IOW - don't crimp (poke) the seam into the wire.
Good luck,
Rick