Give them fresh water twice a day - Make sure you check their water a couple of times a day and change it if it has hay, wood shavings, food or poop floating in it. For some reason, my rabbits always seem to get a piece of poop in their water. Don't know where it comes from, but that's why I always check that their water is clean. You can also use a water bottle rather than a bowl, although, when I tried that I discovered they kept knocking it onto the floor no matter how securely I tied it and then none of them could have a drink.
Buy a good cage - If you're going to take care of your pet rabbits correctly, they need a large enough cage that they have room to move around. My rabbits started out in a cage about four feet by two feet but, with four of them, I quickly realized it was too small. Mine are now in a pen that I made out of cube shelving. You can buy cubes of wire shelving at most hardwear stores or Target and then make a cage out of them yourself (which is great, because you can design any shape or size you want, just buy more shelving cubes!). My 'pen' is around seven feet long and four feet wide, and it has two storeys at both ends of the pen, so that the rabbits have something to jump up on and can sit off the ground if necessary. Whatever you use, make sure it's easily cleanable and that your rabbits have enough room to move around.
Secure electric wires - If you let your rabbit outside his cage and into the house, make sure you have all the electric wires taped up and away from him. Rabbits chew through everything and a quick chew through an electric cord while you're not looking could send him quickly to bunny heaven.
Make sure your pet rabbits have enough toys - Rabbits get bored very easily, so sitting around all day in a cage isn't good for them. Make sure your rabbits have enough toys - plastic balls, hay balls, cardboard boxes, old books they can chew on, newspapers, etc. They need toys so they can wear their teeth down, if not, they get too long and can cause health problems.
Pick up your rabbit carefully - Most rabbits don't like being picked up, so make sure you pick yours up properly. Do not pick your rabbit up by the scruff of his neck. It's cruel. Pick him up with his bottom supported by one hand and his front end supported by your other hand and press him into your body so he feels completely supported and not in danger of falling.
Trim your rabbit's nails - Make sure you trim your rabbit's nails often. House rabbits, especially, get nails that grow very fast as they aren't able to wear them down. This is very unhealthy for a rabbit as it can cause feet problems, so make sure you check your rabbit's nails at least once a month and snip them slightly with small nail clippers if they're getting too long.
If your rabbit is sick, take him to a vet - Many rabbit owners try to nurse their rabbits themselves rather than take them to a vet. If your rabbit stops eating for more than 24 hours, gets diarrhea for more than 24 hours, or is generally looking ill, take him immediately to a vet. This really can be the difference between life and death as rabbits have a tendency to get sick and die very fast. Sure, it may cost you some money, but isn't that better than losing your pressure rabbit?
All in all, following these common sense tips on how to properly take care of a rabbit will make sure your rabbit is happy and healthy and you enjoy having him as a pet too.