1/ Take out appropriate insurance that covers all winter sports expenses (civil liability, credit cards to cover lift passes, Carte Neige, etc.)
2/ Make sure you have all the right clothing and that it is good quality: anti UV goggles, high SPF sun-cream, warm, waterproof clothing, gloves, hats, scarves, tights, snow boots, ski helmet and back protector. And good quality, properly adjusted skiing equipment of the right size.
For the summer, good walking shoes, a well-balanced back-pack, windcheater, etc.
3/ Prepare physically and develop your muscles ahead of your stay: swimming, walking, cycling, climbing the stairs are all good preparation.
Once here, remember to do proper stretches and warm-ups before heading for the slopes.
4/ Get all booking paperwork ready in advance (accommodation, lift passes, ski hire, etc.)
5/ Think about your journey: check your vehicle: tyre pressures, fit snow tyres, or carry snow chains or socks. Practice fitting these items.