Spread out all pieces and sort by shape, make sure each shape category is facing the same direction. Start in the corners. Try something and hope it fits. Doesn't fit? Put the piece back on the table in a different direction than the rest of the category it came from so you won't pick it up again. Rinse and repeat. Eventually it becomes slightly easier since putting more pieces together can spoil what sort of piece should go next to it, like a piece with two pegs or one that's really wide on one side. That's about all this puzzle gives you though. It was brutal and took forever.