I found a nice article over at Home Barista on an Introduction to Barista Techniques.

The post is actually one part of a larger end-to-end on Espressos. About the beans, fine details on grinding, machines, cleaning, etc…

This one part is an important topic of the day, the actual act and timing of making a great Espresso. From the post: Barista technique breaks down into three time scales and skill levels:

• The first is the minute or so spent grinding and making the shot.
• The second is the time spent carefully tasting an espresso or series of espressos, identifying the flavor balance and defects, and making adjustments to ones pull or machines to correct them.
• The third is acquiring experience and informed preferences with a wide range of coffees, blends, espresso equipment, and alternative techniques.

If your are looking for maximizing the flavor in every Espresso you make, take a look at their in-depth walk through of what makes a difference. http://www.home-barista.com