At first it takes awhile to get the feel and techinque down. After the second or third string job, you should be pretty comfortable with stringing.
I recommend first reading up on how to string the racquet, read the stringing instructions that came with your stringer or go online before you attempting to string the racquet.
The most crucial part of stringing IMHO is to make sure you properly mount the racquet to prevent damage of the racquet and harm to you.
IMHO, the people who complain about bad string jobs and deforming/damaging their racquets are the ones that don't follow instructions and don't take precautions on stringing and mounting the racquets.
The quailty of the string job is all about the person stringing it. IMHO.