Well, the answer to that is a little bit tricky because professional baristas in coffee shops usually use state of the art equipment to brew your coffee. Espresso machines designed for the house are probably not going to offer the exact same result.
However! There are a few things you could do as a home barista to improve the flavour of your coffee!
1. Tamping and Channeling -
Many people tend to think they need to use a lot of force when tamping but this is not the case. Tamping is a process that helps you avoid any channeling, meaning your water passes through the coffee bed evenly.
Instead of using as much force as possible when tamping, you should make sure that you achieve a straight and even surface on the coffee bed. It is important that the powder is compacted and dorms a uniform surface so that the water can pass through evenly. By doing this, you will achieve an even extraction without any channeling.
2. Grinding -
If the grinding degree is incorrect, the coffee cannot be extracted optimally, it is either over- or under-extracted. This can completely destroy the taste of the coffee.
For example: The grind degree is too fine for the portafilter - then the water needs too much time to flow through the coffee powder and bitter substances and tannic acids are dissolved that you actually don't want.
However, if the grind degree is too coarse, the water can flow through the powder too quickly. The coffee becomes thin, flat and has an underdeveloped taste because too few components have been extracted.
So make sure you play with your grinder and coffee machine for a bit, pull a few shots and try to figure out which grind setting best suits your taste.
3. Opt for speciality coffee -
You put a very expensive machine from a really great brand on your kitchen counter, but then you save on coffee because according to the motto: The machine takes care of the rest!
Unfortunately, this is not the case, because even an expensive machine cannot turn bad coffee into gold. That is why I recommend you to start buying speciality-grade coffee. Such a coffee has been harvested, processed and roasted with utmost care.
Your taste buds and even your health will thank you! When choosing a coffee, the price should not be the only decisive factor. Paying attention to the purity of the coffee, the roast and the type of bean is also very important.