The old saying "begin with the end in mind" holds true when making the perfect espresso. The goal is to extract a rich clean cup of available coffee oils that are on offer from the roasted beans. So how do we do this?
One often overlooked element is maintaining a clean, well maintained work space. Ensure that your equipment and utensils are clean. It's a good idea to get in the habit of cleaning the machine and porter filter regularly after use and between shots.
The same is also true when it comes to your ingredients. Water should be fresh and filtered, if possible, as regular tap water can taint the final cup. Fresher beans produce a better espresso, which should be viscous and full of flavour with a good crema. Stale beans will result in a coffee that is thin and flat-tasting.