Lots of times when I'm fishing I see bass swirling at the surface or jumping, but every time I cast there I don't get any bites. Any ideas why this is?

  Might not be bass.  If a bass swirls in the lily pads, or is definitely out chasing bait on the surface, you will often get a strike.  But a lone fish "swirling" on the surface out in open water is far more likely to be something else, especially a gar.  If you verify that it's a bass, then I don't know what.  Maybe you have to match the hatch.

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R. B. says, "Take a kid fishing today; you are sure to learn something."    

Throw on a Hexangenia Dry, in about a size 4, and Hold on at Sunset!!!  ;D  Then again, it needs to be the month of June here in NH for the Hexes to be going off. Other then that, try a Royal Coachman...

     Oh yeah, you'll need a Fly Rod.