Ahh, now that I can’t tell you. It’s a trade secret…just kidding.
No really, if you want to know the best way to learn is to go to chiropractic school. We have somewhere around 350 hours of class on this topic. (Divide that up into 2 hour segments 3-5 times a week.) So, you can see that it’s probably not a good idea to let your medical doctor adjust your spine (or any other untrained person), even though that’s in their scope of practice. (I’m not sure why that is.) It takes a lot of practice. It’s kind of like a concert pianist. They make it look easy, and to them it may be. It’s only because they have practiced for years and years so that they don’t even have to think about it anymore.
Now general adjustments can be done by yourself, or someone giving you a big hug. That is motion in your joints, and they just happen to pop, that’s great. A chiropractic adjustment should be more specific. I hope I can summarize this. Your doctor will try to isolate the pain generating joint, and determine the vector of thrust required to take that joint through the corrective motion. Then, through body positioning, he will attempt to lock out all the joints around it so that they aren’t moving when he applies force. At that time he will deliver a high velocity low amplitude thrust with the appropriate contact in the appropriate location and in the appropriate vector to enable the correction. Adjustments can be rotational, gapping, flexing, etc., or any combination. Basically what ever way your joint can move it has the possibility to be adjusted in that range of motion.
I hope you followed that. After all it was your question. I hope I explained it well enough. Please comment if you have more to add, or still have questions. If you want to experience an adjustment feel free to set up an appointment. My contact info is always at my site over in the links (just to the right up there on the main blog page).