Both theory and practice are very important. Making good things depends on the theoretical basis you learned in school, the flexible application in your life, and your own understanding and continuous practice of the word "beauty", so as to constantly improve yourself.
If you are determined to get ahead in this field, you'd better apply to the Academy of Fine Arts. An excellent designer should have a strong aesthetic foundation. Hand-painted, colored ... is very important for designers. Learn AutoCAD, 3dmax, Photoshop and Lightscape. ...
These drawing softwares are not enough. People who know this can only be cartographers. Designers should have something in their minds, ideas and creativity. These things can't be learned by training institutions all over the street. Compared with students in professional colleges for five months, the result can be imagined. Don't deceive yourself. It should be said that it is still good in the whole country, and the difference may be that the salaries in different cities are different. I hope my answer is helpful to you!