If having trouble getting takes on the bobber,errr visual depth regulator, you may need to work on your visualization technique.
You can't just sit there and stare at the bobber. It's considered poor manners, just like staring at a womans breasts.The fish (and the women) won't go for it.
You hafta kinda use peripheral vision and seem to be staring at the ducks or something on shore before the bobber will go down.
Don't ever loose complete visual contact though as that's when it's sure to plop down and back up as you look back. Happens every time.