1. Getting into the car on the passenger side when you're the driver (novice mistake #1).
2. Taking your right hand turns tight and/or without looking both ways for traffic.
3. Taking your left hand turns wide and/or spending too much time watching for opposite traffic.
4. Turning on the windshield wipers instead of your turn signal (since they are on opposite sides).
5. Neglecting your rearview mirror, since you're not used to looking for it on your left.
6. Hugging the shoulder, which may not really be all that bad an idea.
(And not related to the side-of-the-road issue, but related to driving in Kenya:)
7. Not knowing how fast you can go, because there are no speed limits, but you can still get pulled over (by a cop standing on the side of the road, because they have no vehicles) for speeding, though they have no radar gun or other monitoring device.
8. 3+ lane roundabouts. Enough said.
Here's a map of where in the world they drive on the right (red) or left (blue). Interestingly, although most of the world used to drive on the left (including the US), only 34% of the world currently does.