The liveaboard. A week of pure, unashamed luxury and indulgence enjoying your favourite activity. It's expensive, tiring and keenly anticipated so what can you do to maximise your enjoyment? The following is based on experience of Red Sea liveaboards.

1. Check what luggage allowance you are permitted. Many airlines allow extra weight if you are diving but never seem to tell the check-in staff so take copies of any correspondence concerning allowances to show at the desk and have your certification card to hand. Even then, you may have to argue at the desk. Happens to us every year but they always let us on...eventually. Take your regs on as hand luggage. That cuts down the weight of your bags and is a precaution against less than careful treatment of bags by the baggage crew.
2. Take out all the clothing you've packed. You will be barefoot on board and you only need two of each of the following - swimsuits, tee-shirts, shorts, undies. Add a fleece for the airport or post-dive warming up. That's it. Longish skirt or trousers for the airport will double up for your last day when you will be shore-bound and shopping for gifts.
3. Pack a medical bag. The boats are usually well-catered but it is a good feeling to know you have your own antiseptic cream/eye drops/seasick pills etc. Pro-biotics are brilliant if you are liable to a delicate stomach. You have to take them for about two weeks before you go but I have not been ill on board since I took them. SwimEar is a good addition to the medical pack, too. A small spares kit is useful. Again, the boat will be well stocked but a few 'o' rings, lanyards and mask/fin straps are a wise precaution. Batteries and a spare memory card for your camera are also sound ideas.
4. Take something to read. Nothing too taxing.
5. Sun tan cream if you're daft enough to stay out in the sun on board. Lovely cool breezes make it deceptive at sea and you will fry like a bacon slice if you aren't careful. After-sun for when you haven't listened to advice.
6. Towels and dressing gowns are usually provided on board but if you can get hold of a travel towel, they are lightweight and very useful because all the boat towels look the same.
7. Beer is usually available at a price but if you want your own particular tipple, take it with you.
8. Doing all the dives is fun but not compulsory. If you are chilled or tired or feeling seasick, don't feel pressured into diving anyway. You will be gutted when everyone else comes back raving about the whale shark but then who is to say you'd have been looking in the right place anyway? Just smile politely as they babble on about it being the best dive ever and plot a sinister revenge for a later date.
9. You need less cash than you think. Enough to buy a few presents for home, a lunch or two and tips for the crew and that's about it. You will usually settle your boat bill by credit card.
10. Take a magnifying glass so you can see all the teeny tiny things that live in the coral.
11. Boat toilets. You will be told not to put anything down them you haven't eaten, not even paper. The paper goes in the bin. Gross? No. There will be a hosepipe thing next to the toilet. How do I put this delicately? Let's just say that the toilet paper is for drying yourself. Got it?
12. Relax and chill out. Things go wrong on boats and sometimes the weather means plans have to be changed at the last minute. So what? You're on holiday so go with the flow.