The most frequent error made when jig fishing is retrieving them TOO FAST. The one exception is when fishing for spanish mackerel - then it must be rapid where the old theory is "if we're catching blues, we're going to slow for the spanish.
Otherwise. let jigs hit the bottom and work em' back along the bottom "slowly." Unless of course you're at the Lesner Bridge during the last hour of either tide.....Then we've gotta' just cast em' - and hope for the best in that current.
But a slow retrieve will hook you up with anything that hits a baitfish - including flounder.
My personal largest ever caught was there - at the bridge at night. Weighed in the next morning at the fishing pier at #10lb 8oz.
Ha ! He came off the hook at "the lip" of the waters edge, and I slipped behind it (in waders) and KICKED IT up on the beach.

Back to assasins; Also try "Carolina Rigging"them, like for freshwater. In a stiff current I can even use a 2 ounce sliding sinker - for assasins and sassy shad.
And I "beef up" that two feet of leader using 20 pound mono or flourocarbon.