I started off with a Hubsan x4 107c and am now flying a diy mini-drone using the Hubsan components but with my own frame. I posted a thread in the First Build section of it.
While I'm certainly am still somewhat of a novice I thought I'd throw out my tips that probably apply to most of these tiny quads.
1. When you crash or think you're going to crash, cut the throttle immediately and to be totally safe turn off the transmitter. While others have suggested this is to avoid breakage of propellers which is certainly valid, a better reason is to not burn out the motors. I fly my K6 mini-quad outdoors exclusively and when I crash it at least one of the propellers will be unable to turn because of grass, twigs, leaves, etc. If you do not cut the throttle, the current going through the "blocked" motor will cause it to overheat and eventually burnout. Cutting the throttle or turning off the transmitter immediately will prevent this.
2. When looking for a downed mini-quad, resist the temptation to run the motors to be able to hear where it is. Again, most of the time in outdoor crashes at least one of the motors won't be able to turn freely and you will burn out a motor.
3. Avoid flying your mini-quad when it is hot outside. Hotter air is less dense so the motors have to work harder to generate sufficient lift. Working harder means they will run hotter and I believe overheating is the reason most of these motors fail.
4. When flying outside, do not fly with the propeller guard on. I believe the propeller guard is about 5g. Inside this extra weight is not too much of an issue because unless you have an extremely large indoor area to fly in, you will generally not be pushing your mini-quad to it's extreme. Outdoors is another matter and you will find yourself flying the mini-quad quite a bit more aggressively. This extra 5g of weight when flying aggressively will again cause the motors to have to work harder increasing the likelihood of burning out a motor.
5. Resist the temptation to add a bigger battery. A larger battery means more weight which means the motors have to work harder which means they will run hotter. They will also draw more current so the battery will get hotter also. I flew my original Hubsan a few times with a 500mAh battery but while I did get longer flight times, after the flight the motors would be quite hot as well as the battery. My K6 diy mini-quad take-off weight without the camera unit is about 5g lighter than my stock Hubsan. Consequently the motors don't have to work as hard and most of the time after a flight, the motors are only slightly warm to the touch, even with a 500mAh battery.
Hopefully you will see a common thread thru these tips; do not over stress your motors. By doing so they should run longer avoiding the necessity of getting out the soldering iron and replacing a motor.
One last tip, the first time you think "I wonder how high...", "I wonder how far..." or "I wonder how fast...", just throw your mini-quad in the trash. You will save a lot of time in not being able to find it!
Bruce