Last in, first out
Take down the aquarium last when packing and put it up first on arrival. This minimises the amount of time your fish spend in poor water conditions.
Location, location, location
Make sure the aquarium is sited near electrical outlets for the water pumps / filter and try to eliminate the tank's exposure to sunlight, reducing the formation of algae.
Take your water with you
Transport as much of the water in the aquarium to your new home as possible. This minimises stress on the fish as they can get used to the new environment more quickly and adjust better to changes in water chemistry when you do your 10-15% water changes every week.
Pull out all of your decorations and place them in spare buckets or boxes for the trip. Carefully inspect each piece to make sure you do not have any fish or animals hiding inside a hole in a rock or a hollow in a castle. Remove live plants from the tank and place them in a bucket or two of water for the trip.