I am an "no lines" person. I hate working with lines and keeping them straight and just the looks of lines... so I am at a disadvantage with your prints...HOWEVER I do like what you have done! It has a nice style. But you do need more color. with the white it looks to washed out. THe blue however, looks great. Red might be good too.. with the blue in the squares in the block, maybe a dark red sashing between them all? Color and separation. I think separation will help greatly is stopping the lines and strips from being to busy and so much "eye motion" and with all the white in the prints...it needs color to not look washed out.
I am impressed with your work! A great job from shirts!