I used the EPS (Elizabeth Percentage System) for this top-down all-in-one-piece shirt.

I cast on 90 st for the neckband, and after a few rows of 1x1 ribbing I placed the markers to mark off sleeves, back and front. I knit all in stockinette, increasing on every right-side-row, before and after each marker until the raglan was long enough to reach the armpit.

I knit back and forth for the entire raglan part, then switched to the larger needles and knit in the round till the end.