First, I made her a really simple knot-top cap. It is modeled after my favorite store-bought newborn cap that I bought for Oscar years ago. I sketched out a simple template for you, which you can print out HERE. You'll need to cut two pieces of stretchy knit fabric from the template, and then another rectangular piece for the border at the bottom. I cut my border piece to 3 inches tall, and double the width of the bottom of the template piece. I'm not going to go into detail how to piece it together, but Make It and Love It has a really great baby hat tutorial that should give you a pretty good idea. Keep in mind that her hat brim folds up, but mine does not.
I also have basic instructions for a really easy baby hat from a t-shirt sleeve from my early sewing days - you can find it HERE.
Besides long sleepers, my favorite newborn clothes are the basic kimono-style snap shirts you can buy in packs. I even did a tutorial a few years ago about how to dress one up with ric-rac and some pretty buttons (find it HERE). For this shirt, I simply added a lace trim around the shirt's opening - really easy, really fast. This is actually the exact shirt that Oscar wore home from the hospital, and possibly Ruby, too (I don't actually remember what I put her in).
So there you have it, possibly the easiest coming home from the hospital outfit, ever. Add a pair of leggings and some cute socks, and you're all set.
