I think the fundementals, if you're new to skipping:-

1. Make sure the rope is the right length. Normally they come with some kind of guide as to the right length, but too long a rope will definitely cause you issues - especially when learning.

2. Keep your elbows close to your body and your hands reasonably low. Most times, people flair out their elbows and start using their upper arms to compensate for the rope being too long. Moving your elbows out, or using your upper arms will tire out your shoulders before your cardio system gets any workout.

3. Don't jump too high - a few inches, no more.

4. Concentrate on swinging the rope, make sure both your hands are involved, and work on your timing - so one swing, one small hop with both feet. Get that down, so you can do over a 100 turns without a break, then it's time to move on to some other steps / footwork.

5. Good absorbing footwear is important, and the surface, too. Something with some give - so a sprung gym floor, or some rubber matting if you're skipping on a solid floor.

6. Some people find music helps them with timing and rhythm.

Also, like others have suggested, I found books on the subject very helpful - they helped me correct fundamental issues. I bought the Ropesport book, and Buddy Lee's book - both are good.

And this is just a bit of an odd suggestion, and I suspect one that some people will find odd, but I've found them very useful - there's a ropeless skpping rope thingmy called the Jump Snap. Basically, two biggish plastic handles, one has a kinda computery thing in, and a small bit of rope, with a rubber ball on the end of each one. The idea being some fitness device for the infomercial TV channels. Their rationale being that skipping is really good at burning calories, but many don't / won't / can't skip because of the skill involved.

Now I'm not suggesting using one as a substitute for skipping, but as somebody who's already skipped for years, I do find mine useful - it's good for learning new steps or drills, when you'd likely get many misses when trying with a rope. So you can get the learning down without a rope, then when you try it with a real rope, the movement and coordination isn't alien. I've found mine very useful for that. Plus you can use 'em easily inside, when travelling (say in a hotel), or when the weather is truly awful outside (I skip outside, and the wind seems to make the biggest difference to me).