Well, finally we can make sky!, no one has been able to in the history of mankind, but now we can, in game form obviously, I dont mean make a big sky outside, if you can do that, then you should write a tut about it :P.

Now making a sky is like making a cover around your level, some people just make a big hollow block around there maps but I wouldn't recommend this as it makes it difficult for vis when compiling and will make it take hours, as well as making your map lag a lot more than it would with a decent sky impletmention.

so basically all a sky is, is any block / object with a sky texture across all of its sides. so simply make it as you please, you can have as many bits of sky as you want, as the sky in game will always line up, dunno how that is, something to do with the wind I think, (when i say line up i mean when you look at it, if you have a gap in worldcraft between sky pieces then it wont line it up)

The texture for the sky, is actually called grass, no actually its called sky.(what a funny guy)*slacky

Also select map from the top toolbar and select map properties, and you can see a box where you can tell it what sky you want, it will look in the gfx/env folder or wherever the mod or game you have keeps its skies, you dont need to use the cl_ bit, just type in a sky like "hairyface" without the quotes.

Recapping

Use the sky texture on a block to make sky. To select what sky you want select "map" on toolbar then "map properties" then in "environment map" select the sky name, the skies can be found in the folder named gfx then in env.

Best Way to Make sky

The best way is to make it as you go along, it all depends on the way you have layed out your map, you must think about the sky when you are making your map, its very important, if you dont then certain areas will be cut off from view and look crap. you can use a big box sky if thats the way your map is layed out, in counter-strike italy uses this, (however it doesnt go underneath, so it wouldnt take as long to compile if it did and be less laggy) and in tfc 2fort only has one bit of sky across the top open area, as its all indoors from then on, you dont need sky around the whole of your map, just where the player needs to see it.