It seems that we are in full fashion of the worn, and that is why the designs are also pointing to this fashion and people are focused on creating things that have that look that looks so great sometimes.
The tutorial that I leave you linked below is quite interesting because they explain everything graphically and with few words, so it is easy to understand even for a person who does not speak a single drop of English.
Don't miss it as you can learn a lot about vector design.
Walkthrough | SpoonGraphics