Oh wow. This is a great question. It has taken me 6 seasons to figure this sale out, and I still mess up occasionally. However, I get better and better at plotting and planning.
Here's my loot from last year: https://youlookfab.com/finds/c.....ction=4595
This is what I kept. I ordered more and sent back some.
Favourite purchases (aside from basics): The Hinge scarf. (A WOW statement scarf, worn all the time. Would not have splurged on it at regular price.) Halogen earrings. (Simple, have worn them almost every day since purchase. Best CPW of anything ever!) Halogen red cardigan. (A super useful cross-seasonal piece that looks great with dresses, skirts, and pants and adds a fun pop of colour to my core neutrals of navy, ink, grey, white).
Least favourite: Halogen red kick crops (I don't like kick crops on myself); Cece bell sleeve top (I can't handle bell sleeves and didn't like the fabric. Too bad because the colour was delicious!)
Other close contenders for favourite: EF asymmetrical sweater. (A core neutral in an interesting and unusual shape at a great price). BP crushed velvet top. (An inexpensive trendy wildcard for casual dress up situations.) Aquatalia riding boot. (A splurge and investment that will be in my closet for at least a decade.)
Past sale favourites include the other Finds. What unites them: mostly high quality pieces, either signature wardrobe items, or statement items, in key neutrals. Practical as well as beautiful. Relatively higher price tag but (apart from the gilet which is a real statement item and does not get many outings in my casual life) excellent cost per wear.