Having ironed my own business shirts for the last 40 years, and working within menswear for the same amount of time, this is how I do it. Firstly if you have new business shirts that need a first iron then it’s a good idea to check the care label to see ironing instructions for heat settings for your iron. Natural fibres like all cotton can take more heat than fabrics with a high polyester content.
Here are my six ironing steps for business shirts.
Iron the collar first, the do front and then the back of the collar.
Tackle the shoulders, put the shoulder line around the narrow end of the ironing board and iron each shoulder firmly.
The easy bit, iron the back of the shirt with more attention to the yoke of the shirt, the double layer of fabric below the neckline.
Flatten out the sleeves as best you can with your hands. Remember here your ironing two pieces of fabric at once so both sides need to be taught. Iron the sleeves down to the cuffs.