Make a skeleton of the story (ie: plot path if the player chooses everything "right")? Flesh out important NPCs? Map out room layout? Then add room discriptions?

Or:

Do everything from the hip as you go along?

I generally write mine out in a Word document first of all, then copy and paste it into the game file once it's partway done. That way, I avoid tonnes of spelling errors.

It's probably a good idea to have at least a vague idea of where your game is going before you start writing it, but I've never gone to the extreme of plotting out every little room and item before starting writing it. Takes away all the fun of the creative process if you do that.

When I run RPGs my games are 99% insperation, .1% peperation, and .9% summer sausage. On a side note I had done NWN, but stoped because too much prepwork was needed. However IF is diffrent, and I hope I can create something playable. I'm trying out other games people have made, but I have a detatched feeling about the PC themself, I hope I can gather some inspreation on IF uniuqe ways of doing things.

I guess it depends how you think.

If you think about going through bit-by-bit, and instead of doing what's needed you think ahead, then you can go through on the fly.

Some people don't think like that, and miss alot of stuff out. Just remember to think it through fully.

... Personally I'm an "on-the-fly" man. I do try to go over a little plan in my head though, and may jot down idea's and perhaps a rough storyline.