Minimize stopping and turns
I drive a manual and I also regularly drive with live fish in buckets or tubs in my car so I dread coming to a complete stop just to start again a couple seconds later because it will wear out the clutch quicker and cause the water to slosh sometimes out of the container. I know this isn't something that effects a lot of people since manual transmissions are becoming rarer and even fewer people are driving with large containers of water in their vehicles but even when driving in an automatic without any fish a lot of time I prefer to look at the GPS as little as possible so if I am given the choice between a route that takes 30 minutes with 3 turns and taking a route that takes 25 minutes but has 10+ turns I will take the 30 minute route 95% of the time