There's a common greeting amongst veteran espresso pullers whenever they come across new fledglings:
"Welcome to countless hours of frustration."
Anybody who has tried to make espresso at home and compares their production to those of high end espresso bars will usually become frustrated, broke, and obsessive — like me.
Australian Roasters/Educators Five Senses has posted an article in which they take a look at your resulting "puck" to give hints on how you can remedy your poorly performing shots.