There is another presentation cast worth mentioning for some scenarios like this. If the upstream presentation is just too dad-gum tricky, cut a wide path to the upstream side of the lie and make a pile cast directly upstream of your target to get a dead drift into the feeding lane with no chance of lining the fish.
The pile cast is easy. Most of us used to do it without trying when we first began trying to cast a fly rod.
Change the angle of your casting arc: lower the backcast and elevate the forward cast. In other words, "aim high." VERY high...not LONG...HIGH. Now, as you launch your presentation cast (final forward cast), give the rod a wiggle before the line hits the water and drop the rod tip quickly all the way to the water. Again, it doesn't take much "wiggle." Just a quick, subtle shake of the grip and drop the tip to the water/ground.
This puts nice "S"s of slack into the line and leader (at least the line) that the current will pull out as the fly drifts downstream naturally.
But you have to be sure to get far enough upstream of the lie so as not to allow fish to see you or be spooked by the casting activity.