The best plan of action is to lay the wetsuit out flat. Obviously this takes up a fair amount of space, so hanging it up vertically is the next best option. Your suit should be stored the right way out and, where possible, try not to leave it tightly folded or creased as that can damage the neoprene, especially when left for long periods of time.
If you do decide to do some open-water swimming, make sure that you rinse your wetsuit out thoroughly with cold water as soon as you can and then hang it inside out to dry. Some brands also recommend hanging them from the waist so that it doesn’t stretch the shoulders long-term.