Your t-shirts are special and need to be taken care of accordingly. Here are some things you might want to keep in mind.
Go easy on it
Your printed t-shirts require gentle machine wash only. Wash them reversed (inside out). Do not dry clean them or wash them by hand. Wash white and colours separately (We promise we aren't racist). Dry it revered.
Don't bring the heat
Iron your t-shirts inside out. Your t-shirts are pure cotton and can't tolerate excess heat. If possible use steam iron. And whatever you do, do not iron directly on the print.