yes, drifting will help extend the stroke, but I think a really good thing to try is to shorten up your line and really work on a nice smooth application of power. Then, little by little, add more line until you are casting as far as you want to without tails, remembering to extend your casting stroke as you add more line to the cast (and BTW--keep in mind that everyone tails sometimes!).
Where do you notice the tails happening in your cast: early on (soon after you stop the rod on the forward stroke), or right near the end (close to the point when the line/leader junction turns over)?
the interesting thing about casting is that, the more line you have out, the less actual effort you seem to need IF everything about your technique is sharp. When I was doing my Spey certification I had the pleasure of watching Brian Niska ("Whistler" here on the board) cast an entire 5 wt line with a perfectly pointy loop, perfect turnover and no tails. Brian is a Master Certified casting instructor and his single hand casting is beautiful to watch, and what is most interesting to me is that he doesn't really look like he is trying very hard to throw all that line. His technique is flawless, so he really doesn't have to wear himself out pounding the line out there.
Loop Canada Pro Staff
FFF certified casting instructor