Drawing manga clothes: shirts and sweaters

Here's a little drawing I did to demonstrate the differences between shirts and sweaters in drawing, and where you should place the wrinkles.

So with T-shirts, the fabric doesn't come up off of the body too much, because the fabric is thin. Wrinkles go in the standard waist, shoulder, bicep, and elbow if the sleeves are that long. Take some time to look at a few references, or just your own shirt to look at the direction of the wrinkles. Older girls will have some wrinkles under their chest.

For sweaters, turtle necks, Hoodies and the like, the fabric is thicker, so you need to be sure to draw it a little 'off' from the body to show that volume. because they're thicker, they tend to be heavier. This makes their wrinkles actually 'fall.' sweaters will have fewer wrinkles than tops made out of thiner material. Hope this helped!
For sweaters and other heavy materials, I suggest you look at how they fall, whether from a reference picture or something you're actually wearing( that's what I did for the top left xD ).