Since that time I remembered some of the "rules" considered about direction to pick a lock. Mind you, these are rules I made for myself to remember, and as with most rules, there are exceptions, but I thought I'd post 'em here to help others out. All rules stated assume that the keyway is orientated with the pins at the top of the lock.
1. The vast majority of padlocks are unlocked when the cylinder is turned in the clockwise position.
2. Weiser entrance door knobs are turned clockwise to unlock. Kwikset, I believe (pm me if I'm wrong) are the opposite. Schlage commercial locks will generally unlock by turning clockwise (unless special function such as classroom, etc) Many knock-off brands I've found turn counterclockwise to unlock.
3. Deadbolts, whether single or double cylinder, are a bit of a different bag of tricks. Here's how you tell:
a.) stand on the keyside of the door. If the door is hinged on the right and the lock is on the left, you turn the cylinder clockwise to unlock.
b.) If the door is hinged on the left and the lock is on the right, you turn the cylinder counter clockwise to unlock.
4. On vehicles, the driver door is turned clockwise to unlock (more than a few exceptions) All ignitions (on Amercian vehicles) are clockwise to turn of course.
5. Cabinet, sliding door, cam locks, are difficult to tell without knowing the exact lock construction and usage. Many of these locks can be fitted to work in a variety of different capacities, so you have about a 50/50 chance of being right.
6. Mortise cylinders are generally picked in the direction that the latch it activates points. This means that if you are standing on the keyside of the door, and the latching mechanism points to the left, the cylinder must be picked in that direction as well.
Hope that helps.
*NEW*
For some time there have been many questions on what order to pick the pins in a pin tumbler lock so I'd like to take a bit of time to explain the theory of common practices and the success/failure of each.
The optimum situation for any lock picking enthusiast is to be able to attune their sense of touch so that by inserting their tension wrench and pick into the lock, and lifting each pin in turn while applying ever-so-slight tension, they'll be able to tell the order in which the pins need to be picked.
After you've had a basic understand of the tolerances that allow a lock cylinder to be picked, you will understand the concept of mis-alighned holes along the axis of the cylinder. The question may come up, "Why with worn locks does the most common order tend to be from the back of the cylinder to the front?"
This is the answer to your question.
Each time a key is inserted into a particular lock (whether by the correct key or not) The pins are each raised a certain number of times. Thus, a 5 pin lock, operated by the correct key, will have the 1st pin in the lock moved 5 times, the 2nd 4 times, the third three times, the 2nd twice and the last pin only once.
ONLY the last pin in the lock will be lifted to the correct height each time the key is used. ALL of the other pins will be incorrectly lifted at least once.
That said, you can easily imagine what the wear pattern on a lock is going to be like. The front of the lock will take much more use and abuse than does the rear of the lock.
Many of you will by now realized why picking from rear to front can become a common method, but I'll explain just for those who do not quite fully grasp it yet.
As each pin is lifted (again because of mechanical tolerance) it shifts and binds slightly in the pin chamber, causing damage to both the pin and surrounding chamber. Over time, this wear increases to the point where the pin chamber is no longer round (it never was perfectly concentric before of course) but can become obvious to the eye that it is oval or misshapen..
Thus, the wear on the rearmost pin chamber may be almost neglible while the front has become damaged to the point where it can become problematic.
This widening of the hole also affects it's relationship with the shell chamber above the plug, allowing the cylinder to actually be turned slightly, yet still allow the top pin to easily retreat into its chamber.
In effect then, the rearmost pin may have to be perfectly lined up with it's topmost chamber, while at the front the plug can actually have heavy tension applied to it and yet still allow the pin to be raised to the proper shearline..
This means that two similarily pinned locks can have greatly different levels of difficulty (everything else being equal) depending soley on the amount of wear evident in the lock.
Quality and lock tolerances will also greatly determine the difficulty of the lock.
This explains why the pyramid method of lock picking on a new lock is really the best way to learn.