When Annie brings coffee to Dale and Harry, Dale's cup is facing down to the plate. The shot goes back to Annie and then back to Dale when she pours the Coffee and the cup is facing up. Dale couldn't have turned it over as his hands are still at the exact same position.
The playing cards Leo picks from Windom Earle's hand display the faces of [from camera-view right to left] Donna [queen of clubs], Audrey [queen of diamonds] and Shelly [queen of spades] . When Windom Earle has Leo picking the king [Agent Cooper], the 2 outside queens, Donna and Shelly, have swapped places with Donna on the left and Shelly on the right. Already in the next shot of the cards they have resumed their original order.