T-Shirt Design: Piece of Shit initial mock up

Here is my simplest design which I created on photoshop from an idea I'd sketched on paper. It's not brilliant and I could perhaps refine it if I had more skills, but I'm not a fan of drawing on photoshop, I'd rather sketch the designs out on paper and refine them, then photograph / scan and really perfect them in photoshop. But since none of my sketches are refined yet (I haven't decided what medium to use...acrylic, sharpie, watercolour etc??) I'm having to use photoshop to get a rough idea of what my designs will look like.

I saved the above file and placed it into my illustrator document where I copied it across several t-shirt colours. I think it's quite effective and I do like it, however I'd like to see what some other designs would look like in the same style, and also what it would look like if the design was hand drawn.

It was suggested at college that I sew on my designs to create a more 3D effect with my t-shirts. I think this is a great idea but is going to be very time consuming, however I'm definitely going to give it a shot! It would also be harder with the more complex designs where more fabric would be needed, so I'll probably start off with this design.