I think where the guy is pressing the tab key once or twice is necessarily where he iz going wrong.
I always shoot from the most zoomed out view where you have the red crosshairs - I find this the most accurate. I also didn't think the game would let you shoot from the other views as IMHO they are reference views and my version won't let you shoot from those views anyway
Like the other member said, use the "practice missions" in the training academy - they take like no time to load up and can be played over & over.