Quote Originally Posted by li10up
Stay in your middle chainring up front. When you run out of gears to make it easier to pedal, shift to your inside (smaller chainring up front). This will most likely make your pedals have no resistance so you will need to shift to a harder gear in the back.
Actually, this advice can be a little dangerous. You should shift your front chainring before you run out of gears in back. If you are in your middle chainring and shift all the way to your largest cog (or sometimes even second largest) in back before shifting to "granny" in front (if you need it), you have a very good chance of dropping your chain to the inside. Been there, done that! It will stop you dead on a climb, making it very hard to get going again once you stop and put your chain back on. Much better is to shift in front only when you're, say, on the third cog in back. It puts much less stress on your drivetrain and you are much less likely to drop your chain.

I find it pretty natural to take a quick glance down to my front chainrings to see which chainring I'm in, if I forget, and even to glance back between my legs to see which cog I'm in, but I've been riding for years. It can be harder to do on a mountain bike on trails, and it does take some practice. Because I've been doing this on road bikes for so long, I totally forget to use the little gear indicators on my mountain bike gear shifters. I need to remember that those are there for my convenience (and safety)!

Emily