I would say your feel for what's a bite or not will come in time, but keep in mind that it will be harder to detect a small bite or nibble with a medium or heavy action rod with heavy line.
It always takes me a while to get the feel for the tug my jig head creates whenever I bounce it on the line so I would recomend playing around with your retrieve for the first few casts whenever you jig.
When fishing vertically with worms or jigs (as oppossed to horizontally with topwaters and crankbaiting) it seems some pros prefer lighter action rods with lighter jigs heads. Also I would say fish super slowly.
All winter I've been watching some In-Fisherman DVDs I've found at the store and they offer great technique pointers. They also use a lot of underwater camera shots of the fish which are very cool.
Here's one of their videos from their You-Tube channel on "Shakey Jigging" with various plastics.
http://www.youtube.com/watch?v=BIl9IWzJh-o
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