I wrote this as a Facebook comment, and what started as an answer to a question became rather lengthy and in depth. So I thought I'd post it here for future use.
We do One Cast everyday. It's a video where originally we made one cast off the dock and kept track of how many we caught. It's become a little more than that the last couple of years but if you go back and watch the ones we did/do off the dock, we're doing the same thing you'd do off the shore below the dam.
If you're really serious about this, you have to look at all the components of your presentation- your rod, line and lure. You need a long, medium light spinning rod, almost a medium. You can't work and set a hook with a wimpy rod, not throwing off the shore. I'd use a 7-foot rod, at least a 6-6.
Match your line to the weight of your lure. I would try 2-pound Vanish and a true 3/32nd ounce jig. I say true because most jigs out there are not what they say they are. For instance, we carry PJ's jigs. They are almost a full size lighter than their label. Zig Jigs are a little lighter, not as bad. We've developed our own jig and they are very close, within 1/1000's of an ounce. But if you're using 4-pound line, use an 1/8th ounce jig. Play around with it and see what works best. But this combination - line and jig - is very important. And you have to match it to the current/depth of water.
I don't think your cast should be out there as far as you can throw it every time. There are alot of fish just a few feet from the bank most times. Heck the guys out in boats are throwing to the bank's edge for a reason! Think of the area of water in front of you as a wall and paint it... work every inch, then move 6 feet, up or downstream. Don't keep throwing in the same place over and over... the fish are laughing at you about the tenth cast - "I've seen that lure before!" Well... if they could talk.
When you're working the jig, hold your rod high enough to keep the jig up off the bottom but not too high that you can't set the hook, hard and fast. Don't move your rod tip much when you're working the jig but make short, sharp "jigs", giving it slack between moves. You need to make the jig fall - that's what triggers a strike. Yes they will hit it if it's just swinging and swimming but I guarantee you'll catch more if you get it to drop.
Where you land the jig on your cast is equally important. Hitting the right spot in front of you as to current speed and depth of water, letting the jig drop enough, in time to be in front of the fish and get that 3-6 seconds "in the zone" before have to reel and repeat. Throwing above you - that "spot" - and distance of the cast is one formula... both components have to be right. That's where you use your long rod to extend the sweet spot a little.
Gotta work it and practice. Vision in your mind - what is the jig doing? Find out what they want - fast or slow presentation. Change it up till you figure it out -- don't keep doing the same thing if it's not working. Change.... move.