The concept of shifting gears on a bike, has at times become the main topic of conversation in the industry. We've gone from down tube shifters to shifters moulded right into the brake levers. The big TWO have always been Campagnolo and Shimano. Now there is a competitor SRAM who hope to make it "the big Three." But the jury is still out on them. SRAM have taken the bicycle component industry by storm and are prevalent in the professional peloton. I think they came on a little too strong, were a little arrogant in their revolutionary "double tap" shifter and bit off more than they can chew. I think the Andy Schleck incident "humbled" them to a certain degree. Many people argue the point that Andy Schleck lost the tour (2010) because of his SRAM components. I agree that SRAM have changed the way we shift. But the double tap lever is certainly not the choice for me. I think as a cyclist, its easier to have two levers. One for the front derailleur and one for the rear derailleur. I am a Campy or Shimano die hard. I will never go SRAM unless I'm paid to.
Getting back to shifting. There's no "right" or "wrong" gear to be in. You shift according to feel. As the terrain changes you operate the shifters to make it easier or harder to pedal depending on what feels right to you.You have to be pedaling in order to shift, however, it's important to ease the pressure off the pedals when you shift. Below is shifting using the Shimano STi method. You can click on the photo to see it enlarged.