How far do you have to move? Are you able to personally drive your fish to the new place?
Some tips right off the bat:
-Drain tank completely and remove all sand, gravel or rocks.
-Carry fish in temporary containers like buckets or storage bins. Don't put lids on tight. If possible, put an airstone / air pump in each container. Make sure temp. does not fall too low - crank the heat in the vehicle if necessary. Another option is to use fish bags. They can be carried easily in cooler(s) which will keep the temp more stable. Fill the bags no more than halfway with water and try to trap as much air in the bag as possible before tying it off. Don't blow into the bags to inflate them - CO2 does the fish no good.
-Unless the tank is 3 feet long or shorter, don't try and carry it yourself; especially up/down stairs.
Basicly you bag the fish up in fresh declorinated water (not from the tank but roughly the same temp.
Place the fish in a large container like a Cooler or something.
Empty the tank entirely of all water, substrate....Everything.
Take the tank to were it needs to be and position tank were you want it (which is why its good to do it last, because once its full your not going to want to move again because you under estimated the size of your furniture).
Add your substrate and rocks etc.. and fill it with clean fresh water (100% fresh), try to get the temp correct. (Try not to change the heating temp that your heater was already set to....helpful hint) another helpful hint is put a face down dish on your substrate and poor your water onto this to stop it from getting stirred up
Empty the fish only not the bag water into the tank.
Keep a very close eye on your temp and parameters for a few weeks
Oh and another thing, it's important that you don't let your filters dry out to much. you don't want all that good bacteria dying so keep all filter medie in a bucket of your tank water....VERY IMPORTANT.
The best thing to do is look at the links that i have added to this post and follow the steps. It's really spot on. I followed it without any deaths so i was wrapped
I've also been told it is far better to leave the substrate (wet) in the tank. That way it keeps any good organisms you have developed. My cichlids often "chew" mouthfuls of sand and spit it back out, and I know from cleaning my filter that I have some kind of edible harmless worms in my tank that the fish just love to eat.
I also try to keep a good amount of the old water so it is less stressful.
I have had to move my tank a few times... and have another move coming up in a month. Good luck!
I have moved my 80 g African tank three times in the last 5 years with no losses. I always kept at least 40 g of the old water. I just gathered a bunch of those arrowhead bottles and used them. I never took out the substrate and kept it moist. I put the fish in 5 g buckets with old tank water and battery powered air stones.
Probably the most important thing is to rush like **** to set everything up in your new place before your filter bacteria dies. If you're too late, the filter will stink. If it stinks, you have to rinse everything out in hot water and start over with some good bacteria starter. If that happens you at least have some of the old water to help out.
Oh, and don't feed them for at least a day before the move.
I have had several moves as well and the easiest way to do it is to get a large container or even a cooler and fill it with your tank water. Just transfer your fish to the cooler or tub and drain the rest of your tank. Alot of people say to use treated tap water, but as long as your tank water is in good shape, you will be just fine using it. I like to do a good water change to my tank a day or two before a move. I like to bag my filter media much like a fish or keep my canisters full of water during the move. This will help keep the bacteria in your media alive.