Nothing special. I just spread 1/2 cup of potassium 0-0-60 to a 4x8 raised bed every other week after I see flowers. I also try to keep the PH level at 5~6 range. I'm not an expert at all, so someone else may have a better way to feed strawberries. I just use all purpose fertilizer for my garden, and add additional nutritions to plants with special needs.I’m gonna try your potassium suggestion too.
Can you tell us specifically how you do this?