I do several things before the season. Probably most have already have been mentioned, but some are unique to my house. Most of the important ones for me are:
1. Remove the rotating ball vent on the roof and cap it. (It only serves an outside grill which really has quite a bit of ventilation.)
2. Clean up the garages elevating the stuff that I left on the ground during the off-season months. (I have several shelving units that I have built and secured to the ceiling so hopefully they don't tip over in a surge.)
3. Pick up the yard and knock off all the loose/old coconuts. I am trying leaving the other coconuts on this year. The coconuts have to be dealt with in June/July and September since they grow back.
4. Check the storm shutter equipment to insure that I have enough wing-nuts, etc.
5. Insure that I have a couple bottles (3 or 5 gal, can't remember) for the outside grill if the main gas line fails.
6. Fill my 5gal gas cans (30 gals) and add stabilizer.
7. Fill the 400gal diesel tank for the generator. Keeping it full helps but doesn't totally alleviate it pulling up its bolts and smashing into something if we get a high storm surge which apparently we have not seen for about 100 years in this area.
8. Accumulate a couple thousand dollars in varying denominations, mostly smaller bills. Used to save only $100s, but getting change after a storm can be a problem and I have a safe in the house which is reasonably secure.
9. Stock up on canned goods especially vegetables (which my wife and I hate, but are a good source of additional fluids) and get several gallons of bottled water. (I also fill several 5 gal jugs just prior to a storm which is much cheaper than buying bottled water.)
10. Insure the painted axe in the ceiling crawl space is there and functional.
11. Get/replace my battery stock of various sizes.
Just before a storm I have a list which starts at the roof and works its way down the house and finally in the garages, the yard and the boat. (I have a flat roof. So, there are a few things up there that most people probably will not have.)
I also have a check list for after a storm such as cleaning the roof drains so that I don't get a (another

) leak in the house.
Sorry for this being long, but hope that it helps.