Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Is a different way required than in how you use regular GW ones? I frequently find that they don't come off the plastic at all after soaking and you can still see the plastic outline on the model

What do you mean about "come off the plastic"? They aren't supposed to come off the clear film, the "plastic" is the transfer and you dip it in water to get it off the backing paper. Are you getting confused by the ones where the whole sheet is printed on a single piece of film instead of having lots of separate pieces for each transfer? If so you're supposed to (very carefully) cut the transfer you want (including the backing paper behind it) out of the sheet and then soak it.

As for how to get rid of the outline on the model make sure you're putting them on over a layer of gloss varnish, then after it's had a while to dry add another 2-3 layers of gloss varnish to seal it in place before spraying a matte layer to bring the model back to its normal finish. All of the 40k stuff in my gallery is done with FW transfers and, outside of an occasional bit where an air bubble was trapped under the transfer, you can't see the clear film at all.

Yup, what he said.
Also I'd recommend looking into Microsol and Microset.
They make using transfers a bit more involved but the results are great.

I personally like Vallejo Decal Fix after a few coats of Microsol. I find that it gets rid of the edges very well.

Also, if you own an airbrush, hitting the area with the fluid medium of the brand of paint you generally use -- so lahmian medium for Citadel paints, for example -- blends it all together seamlessly.