We've done this a few times and had no loses or illnesses.
Turn everything off.
Take out decorations, wood, plants etc. Drain tank down so you are able to catch the fish easier, but leave enough water for the bags.
Use one bag per type of fish, depending on how big they are and their temperament. Make sure you bag it with oxygen, twist and secure with elastic band. Put each fish bag inside a dark coloured plastic bag. Put bags inside polybox, which you can often get free at LFS. Put lid on, this will keep them warm.
Put all filter media in another bag with tank water and air. Make sure there's enough water to cover all the media, it mustn't dry out.
Drain the rest of the water down. Decide what you're doing with the substrate. You may want to reuise it, so scoop it out into a bucket. If not, bin it.
Make sure no water is in the tank.
Remove heaters, filters etc and package for transport.
At new house. Set tank up, heaters, filter etc. Use the water from filter media bag to put back into filter, and top up if necessary. Put substrate back into tank. Decorations etc. Fill with fresh dechlorinated water, using hot water to get up to temperature.
Switch everything on.
Float fish in bags, then acclimatise as normal.
Hope this helps.