Some pre-season fitness tips...
Improve your overall cardiovascular fitness - cycling, running, 'bunny hops', roller blading and bouncing on a mini-trampoline will help to build up your overall fitness and strengthen those all important thigh muscles.
Feel the burn - strengthen the quad muscles and improve your core stability with squats and travelling lunges and wall sits. I've found a great explanation and demonstration here.
Get to the core - planks, sits-ups and exercises on a gym ball or wobble board will help to improve your core stability and sense of balance.
On the slopes...
Hot and cold - warm up gently at the start of the day with a walk to the first lift and few easy runs to loosen up any tired, achy muscles; don't head straight for the black runs! Watch out for icy patches. Be careful on that 'one last run before we finish' - tired legs, heavy wet snow and a thirst for the après ski are a recipe for disaster (it's sometimes better to skip the last lift and head to the bar early!)
Easy does it - take plenty of breaks, listen to your body and pace yourself. Skiing hard on days one and two will just ruin the rest of your holiday. Most skiing injuries and accidents apparently happen on day three when the confidence levels are high, but energy levels are low.
Liquid lunch - drink plenty of water and isotonic drinks to keep hydrated, and avoid tea, coffee and alcohol. Be careful of the 'lunchtime lethargy' - the wobbly legs and a sleepy head on the first post-lunch run after loading up on tartiflette!
Kit-check - choose your boots carefully - head for a shop with a wide range, get them heat-moulded if possible, and if they're not right, change them. Poor fitting boots and bindings will hinder your progress - no matter how good your technique! Make sure you've got the right kit with you - skiing down in a white-out without my goggles wasn't much fun (it was sunny when I left the chalet!!).
Ice is nice - With an acute injury, use ice rather than heat. Take a couple of plastic bags with you and fill up with snow!
Following these tips will hopefully allow you to make the most of your trip - most importantly, remember that it's a holiday and make sure that you have fun and enjoy it!