Here's my way of thinking....
take a parcel of air in contact with the ground at the equator. Because of surface friction it will be travelling at the same speed as the ground at that point. Let's say that the speed of the parcel is 100kts. the direction of travel is the same as the direction of rotation of the earth.
Now deflect this parcel Northwards to a higher latitude. The speed of the earth's surface at this latitude is (for example) 50 kts. (This part of the earth has the same rate of spin as at the equator, but the earth at this latitude has a lower diameter).
So the earth is moving at 50 kts, but the air is moving at 100 kts. So it will move faster than the surface, and travel eastwards. If you look at the track that this parcel of air takes, it will appear curved to the right relative to the earths surface.
A similar parcel of air near the North Pole will have a very low speed, but if you deflect it southwards towards the equator it will be moving slower than the earths surface at that point. The effect is that the parcel will appear to deflect westwards (ir to the right of the direction of travel) relative to the earths surface.