I think dark blue/navy jeggings/leggings are great for over sized sweaters especially if they just cover your bum. Worn out boots/brown pumps are always good and being from Texas, cowboy boots look good with anything. Pair any big sweater with a messy bun and braid and it looks effortless and autumn-y. With a bright green you want to go darker on everything else besides accessories because it's just too much dark. A good accent color would be a coral or pink. Some pink tinted sunglasses or coral nail polish or blush would put all this together perfectly.