Always have lots of large HD trash bags, a gallon of bleach and a couple of buckets on hand. The buckets will first be used for flushing in the event that the water pumping system in your area goes down (no water pressure), and then afterward, for cleaning up any mud or floodwater residue. The bleach will be essential if you need to clean up flood debris, and may be sold out after the storm. It is also useful for making water clean enough to use on your body if you get water system contamination. Also make sure that your first-aid kit is stocked and up-to-date; not for storm injuries, but from clean-up injuries -- you get lots of cuts and scrapes cleaning up after a storm. Include medical super-glue for closing cuts.
While you are waiting to decide whether to evacuate, put one-of-a-kind items (photos, legal documents, wedding gowns, stuff like that) in waterproof containers and store them high off the ground. Make sure that you have hardcopies & PDF cell phone photos of all home insurance and repair history documentation in a waterproof file and take it with you if you leave. (Do NOT depend on being able to retrieve items from the cloud immediately after a storm.) Get out the pruner and remove any tree limbs that are in any way iffy with regard to your home and or vehicles. If you have a treed lot and do not own a chainsaw, buy one now. Get rid of the limbs once they are down, so they don't become missiles. If you must park your vehicles in a treed area, get something soft like bubble wrap and put it over the windshield to mitigate the risk of breakage.
If you are not allowed to board up windows, cut down cardboard boxes flat, tape garbage bags over them, and then tape them to the inside of windward-facing windows and those that are at risk from flying debris such as tree branches. The cardboard won't stop breakage, but it will help mitigate interior damage if the window does break. Also, put trash bags under towels underneath those windows, so that if they just leak, the water is less likely to spread to the rest of the room. This is particularly true of sliding doors, which are notorious for leaking under storm pressure.
As other people have noted, ice is critical, and the larger the pieces, the longer they will last. Making your own for cooling is better than buying it, because you can freeze it in containers and large contoured pieces. If you use coolers to store perishables, pack them as tightly as possible, and put a layer of plastic-wrapped newspaper or towels at the top to insulate the opening and hold in the cold better. Store them away from sunlight if possible.
On the subject of cash, I recommend about $500 if you can swing it, with at least $60 in small bills for buying things like ice or water. You may need to pay cash for a hotel room if you get damage. Gasoline is critical if you live near an evacuation zone: SAFELY store enough to refill a vehicle tank at least once, in case you have to evacuate and get stuck in a traffic jam. (Also, not pleasant, but if you evacuate, be sure to carry some kind of large blanket or towel in the car; a couple of stiff windshield sunshades are even better. You may need to be able to hold it up so that someone can pee on the side of the road. Last time I was in that kind of traffic jam, I witnessed a young teen girl get in and out of a car several times to try to find a way to shield herself from the view of other drivers, but she couldn't. We were near an on-ramp, and a line of truckers had a full view. She ended up having to humiliate herself on the side of a road with at least 100 people looking on.)
