Well, the most obvious effect would be that the sun would rise in the west and set in the east as would the stars. This would be called retrograde rotation. Currently the earth orbits the sun moving counter clockwise when view from a location north of the ecliptic plane .

Now the earth also rotates on its axis in a counterclockwise fashion. But if the earth rotated in retrograde then this would also effect the difference between solar time and sidereal time .

But other than that and associated effects, there would not be any outstanding difference as far as climate, weather and normal day to day stuff. It would be very strange to watch the sun set in the east!!