...follow the washing instruction carefully for each shirt.  By doing that, you will increase the life span of the shirt and decrease its negative impact on the environment.

...washing, unbutton, turn up the collar and turn the shirt inside out. Use light program, 30 °C or as stated on the instructions.  We do not recommend tumble drying, and never leave the shirt in the machine after the program Is finished as that may cause wrinkles. Washing delicate clothes requires a mild detergent.  Wash light colored shirts and dark or printed colors separately.  

...washing, put the shirt on a hanger and button the collar to achieve best results. Stretch the cuff, collar and front softly, and allow it to drip dry.

...with a light ironing that will give the shirt that extra crisp touch.  When ironing the cuffs and collar, lower the heat setting and iron gently.

...your clothes and do not treat them as interchangeable – always consider repairing before replacing.