This outfit wasn't bad at all, but we are now holding you to a higher standard! "Not bad" isn't good enough for our super secondhand fashionista! You did a great job recreating the inspiration calendar look though.
I love all of the suggestions, so I haven't any of my own to add.
A shell is usually a sleeveless top that you wear under a cardi or jacket. It could be knit, silk, cotton, anything. I think of them as being close-fitting but not tight and not voluminous. I have several sweater sets and use the shirt part of the sets as a shell under other things.