If you're fishing deep with lots of distance between the bobber and the
fly, watch the submerged curves in your leader instead of your fish
pimp when you can and you'll notice more takes.

When the drift is too far away to see the leader underwater, overpower
the mend a little and pull the whole outfit a little tighter underwater
and that'll also help with detection. I think it's worth the temporary
interruption in the drift to get a little straighter leader underwater.

Let your downstream drifts straigthen completely before you strip your
line in or pick it up to cast. Sometimes you've got a fish hooked and
don't know it and of course sometimes they like it swinging and/or
rising at the end of the drift.

bruce h