Prepare to evacuate, just in case. If there is an evacuation, the gas stations and stores will run out of gas, food, water, and ice really quick. You may be stuck in traffic jams for hours. Odds are you will be gone two days or so then will be able to return. Even with a reasonable hit, the worst that will probably happen is that you will return to a house with no electricity for a few days. Most hurricanes are not a Katrina, Betsy, Camille, or Rita but the potential is there. They can change course and do the unexpected at the last moment. Be prepared for anything.
Gas up the car(s), fill up any extra gas cans. Do this early. Whether you evacuate or not, consider this a top priority.
Gather all your important papers and have them where you can just grab them. Insurance, passports, drivers licenses, credit cards, prescriptions (medicine and glasses), such as that.
Pack up your medications.
Prepare an overnight bag, maybe two changes of clothing.
Get some extra cash. Evacuation is expensive.
Prepare some water to take with you.
Park any cars left behind on a high spot in case of flooding.
Think real hard if you have people with medical conditions. Being stuck in traffic for many hours (18 hours form Houston to Dallas during Rita, for example) with a weak, elderly person can be fatal for them. I know. If you have someone like that, either really prepare to hunker down or leave way early before traffic builds up. And realize that with a serious hit, you may be without water, power, and medical services for days. I went through Katrina and I remember the really stupid things many people said about why didn't they evacuate. I'm trying real hard to be nice here.
If you still have time, fill your freezer with as much water that can freeze as you can. Empty milk jugs work great. If the freezer has a lot of ice in it, the food in it will last a lot longer than if it is half empty.
Decide what you are going to do with your animals.
Pick up anything that may become a missile and safely store it away. Sinking lawn furniture in a swimming pool is a good idea if you have one.
If you decide to stay, prepare to evacuate anyway. You may have to.
Get extra batteries and make sure you have a battery powered radio. Being able to get information is critical.
Stock up on foods that dont need to be refrigerated. Dont forget a hand-powered can opener. Plan for no electricity for days.
Have a way to cook food and boil water without electricity. Remember, youll need to wash dishes and may need to sterilize water.
After Katrina, the most important commodity was ice. Imagine the Gulf Coast in August/September with no air conditioning. Stock up on as much as you can.
Stock up on water. Your bath tub will hold a whole lot of water. Think of other big containers you have that an be used.
Have an ax or power saw ready to clean up tree limbs.
If you stay and there is even the most remote possibility of flooding, keep an ax in your attic. You may need to get out through your roof.
Thats about all I can think of on the spur of the moment. Hopefully this one and the others later this year stay out in the Atlantic and dont do any serious damage.