Make sure you keep your filter wet. Put it in a bucket with aquariumwater, not tapwater.
Where are you going to keep your fish? I would suggest you put them in buckets as well with tank water, or any onther container that is large enough. Run a heater in this container if you'll be working for a long time.
Once you removed your fish and filter, take out all decorations and plants (put the plants in water as well).
Remove your gravel and throw it away, or clean it and put it back in.
Clean your tank with hot water.