I don't show but like to have Jack in proper show trim (ie handstripped with a bit of judicious scissoring). I also don't think there's a 'right' way necessarily, just what looks neat and natural.
Here's what I do: I normally leave his natural tail length (about 2-2.5") at the base of the tail for a few inches up the length then trim a
gently curved taper in line with this up to the tip which is slightly rounded off (ie no point). To me this is more pleasing that a straight line. I like to think of it as a carving knife shape with the straight edge being the top of the tail. Takes a bit of practice to get the right shape. Confidence is key and scissors must be sharp. Tip: go slow and steady and don't cut until the tail is still. Jack has a tendency to twitch his tail at the very nanosecond I want to trim!
Hope that makes sense!