When I was a young girl the idea of layering brought to mind women's slips. Nowadays I am thinking more along the lines of tees and tanks.
Layering a tee or tank underneath another top has been done for quite some time, but these days it is not just a little added thing, it can be necessary with certain items, particularly with leggings.
Throw on this Velvet tank tunic with your leggings and then you are free to put on a blouse or shirt of any shorter length to create a slick and textured look, while appropriately covering your bum.
Another great way to layer with leggings, or any skinny pant for that matter, is to add sleeves with the bottom piece. For instance throw on this Michael Stars piece underneath a sleeveless blouse or long vest and you have some added warmth with your legging look.