Anticipation is king. Acceleration sense is what you're describing here, ie. lift off in good time. DON'T select neutral and coast - this will use fuel to maintain engine idle. Modern cars will not inject any fuel at all when your foot is completely off the right pedal. And besides, you'll have to use brakes harder and sooner if you do take the coast in neutral option. So it's a double loss in that way alone.
However, don't wind up following drivers by lifting off ridiculously early, this is not fair and does nothing to help safety in general. If there's nothing behind then of course you can do whatever you like.
I could wring over 40mpg out of my BMW 528i (Auto) by driving with some restraint. Not stupidly slowly, which probably doesn't help economy anyway. But it does make a big difference. Driven enthusiastically I still struggled to get it below 30mpg, a fact that might surprise a few people.
