Do you seem to be dropping your chain frequently, especially in hillier terrain? Happens to the best of us, especially those who are new to cycling. There are a few scenarios that where the dreaded chain-drop is most common-- here's how to make sure you stay smooth:
1.) Shifting from the small chain ring to the big chain ring while going downhill.
When there's a lot of slack in the chain it jumps and lands on the chain rings. As long as the front derailleur isn't moving during one of those jumps, it usually lands back in the right spot, but not always.
To avoid this kind of drop you want to make sure that if you're going downhill, you shift as you build speed, so the chain tension remains steady and it's not jumping around while you're trying to shift. If you go over a hill and coast a bit to recover, then when you try to pedal you're in too small of a gear and you spin your legs really fast but the chain doesn't engage (the wheel is spinning faster than the gear ratio) then you can still shift to larger gears to catch up to the speed, but you need to pedal slowly while shifting.
2.) The opposite scenario: You go down a big hill and it’s followed by an immediate uphill.
You may be in a big gear to go down the first hill but that gear isn't going to work to go up the next. Again, you want to shift gradually as the terrain and gravity start to pull you backwards. Ideally, you'd continue to pedal the same RPMs on both the downhill and uphill, just using different gears to accomplish that pedaling cadence. Do not delay your shifting until you're going up the hill and your gear is now obviously way too big and your cadence slows dramatically. That puts the chain A LOT of tension. To avoid this, as you feel your momentum slowing, shift to a few bigger gears in the back and then almost immediately shift down to the small chain ring. This will give you a pretty similar gear ratio so your cadence shouldn't change dramatically, and your front shift will be controlled. You aren't dumping the chain while it's under load.
3.) You're riding a TT bike with bar end shifters
You want to ease your chain up and down, not throw it up by yanking the lever as hard as possible or dumping to the inside by shoving the lever back down. You don't have to use the full range of motion on that lever. You only need to pull or push it far enough so the chain is on the chain ring that you're aiming for.
4.) You're doing everything right and are STILL dropping your chain
If you think you're doing everything right and you're still finding yourself spending a lot of time on the side of the road picking up dropped chains, it's possible that your limit screws need to be adjusted. FYI: Limit screws are the things that limit how far the derailleur can go so your chain doesn't go off the edge. The only way to know for sure is by taking a quick trip to your local bike shop for a mechanic to take a look. Even with properly set limit screws, you can still drop your chain, but it's best to make sure they are set properly.
Think of the process as a delicate one, keep practicing, and make sure you're bike is adjusted properly. Learning to shift without dropping your chain is a learning curve every cyclist has to face.