1) try to get in the best shape as possible befor you go this will help you to be able to ski more hours in a day and more days in a row it is also a matter of safety. Skiing at a small local moutain for a few hours a week would be ideal, if that is not an option ice skating, or roller blading uses very simalar muscules and movments but even cycling, jogging, or walking is beter than nothing.
2) 8 years ago you may or may not have been on a shaped ski do not ski on old straight skies rent a pair of shaped skis. If you have not skied on them a short leasson on how to ski on them would be beneficial but not nessesary the idea is less pressure and rotary movments and more edging movement (get them on edge and they will turn all by themselves) roll knees and ankles in to the turn think about your foot pressure on little toe on right foot and big toe on left foot to go right then big toe on right foot little toe on left to go left, always keeping pressure between your shin and the toung of your boot (keep forward) youll have more controll and your legs won't get as tired
3) as far as skiing without an instructor the instructor picks terrain that is apropriate for your ability you should start on the green trails to warm up and as you build confidence then advance to the blue or harder trails He also knows lines to take that can make a harder trail seem easier you can do this yourself just look think and make a plan before you start down, the instructor is always there keeping you focused and encoraging you now this is your job don't look at how far you have to go or how steep it is to the bottom just focus on the next turn one turn at a time, the instructor know which lifts service different areas make sure you know were the lift is taking you also the instructor is always looking out for your safety now this is your responsibility look up hill before you go out on the trail ect. know the responsibility code!
4) When your at the top of the moutain don't forget to stop take a breath of the crisp moutain air, take in the majestic views and ponder for a moment the work of the exterior decorator and how bleesed you are to be a part of it all that day.
5) Always keep it fun