yeah, heres what you can do, turn over a card, usually you push over the top card with your thumb, catch it on your middle finger tip and push it over (thats how I do it) now, work out a double lift with the same principal, simply put, make it look as close as possible, if you practice it enough times you can get your double to go off the pack and flip as one card, which I think helps as a convincer.
Another way if you want to know how to look totally natural if your just wanting to change completely, is to hand the cards to your family or friends, and just say, show me the top card, and it's an unbiased show of the top card, don't say flip over the top card, because then they're told to flip it over, tell them to show you the top card, and see how they do it, and you can learn to do it like that.
you don't need someone to tell you how to do a double lift, have your own unique double lift, that nobody else uses, or maybe they do but you figured it out on your own, and that will be the most natural one for you, and the cleanest one.
~Beans
ps. sorry for the essay, but it's a broad topic that should be explained in depth.