Originally Posted by oldbobcat
I'm inclined to say find a new bike shop because it's been a looong looong time since I've eaten **** on a shift, but here are some tips to try before you go back to the shop.
First, pedal at a snappy cadence. The chain has to be in forward motion to make it jump off one cog and onto another, so if there isn't enough motion it ain't gonna jump to well. Start in a low gear and shift up as you pick up speed. As a beginner, aim for a cruising cadence that's at least as fast as walking or running. As you get more coordinated and stronger, your feet will get used to moving even faster.
Second, don't "wimpy-shift." Some riders stop pushing the lever as soon as they hear a click. Keep pushing, not hard, until the lever hits solid resistance. As you get a feel for the levers you'll learn how to find the trim positions in the front (left) shifter.
Third, back off on the pedal pressure when you shift. Keep the cranks turning, just don't push so hard. Anticipate your shift points so you can back off, before you have to keep pushing hard just to keep moving forward.
And if this doesn't work, and your shop isn't being much help, get back to us with some more details. We'll get you going without having to spend another cent.
Alfeng is going to chime in now with his recommendation to buy Campagnolo levers, with the disclaimer that they're not as expensive as everyone thinks, but dammit, some of us still believe you're entitled to at least couple weeks of enjoying your new bike before feeling compelled to swap something out. Make that a couple years.