Definitely nice choice of style. And nice choice of colors on each shirt. Like Lyocell said, give the woman a more feminine look, possibly by making the lips a bit more bulbous or rounded? And dim the chin down on the guy a bit... its just huge, haha. But just a bit, otherwise.
Just a few minor tweaks and I would totally buy this.
Here I made it smaller and some people said they liked the red so I brought it back. I will work on the man and woman features more to make a contrast.
I think you need to more clearly define this as line or shape. You're kind of teetering between both right now, so it makes it feel awkward/uncomfortable. I think you'd be better off thinning everything up and making it a more detailed line drawing (in an art nouveau direction). I'd also consider the tee colors - maybe just tonal line work on a larger scale - the entire shirt maybe.
I have redone the lady but in a wierd way but I think it looks cool. What do you all think about the new lady. I do agree about the compositoin ill work on that