Terminal
When I wing it, I just end up making things incredibly long.

That's just taking the scenic route. ;) (Provided there is still plenty of nice scenery along the way. Otherwise, it's just "the long way." )

Ryuthehedgewolf
Well, I'm trying to get more organized with my story here. So I'm about to write a script that will cover the rest of Chapter 1.

But mostly everything done so far was just kinda done 'loose'. Most of the time I don't even follow the script. I always have something to change, mostly dialouge though. And forget about thumbnails.

They don't work for me.

I do thumbnails right before drawing the page, well maybe half an hour before so that I can "digest" the layout idea and pick up the flaws. Useful for cramming 24 word baloons into 11 panels in a way that makes the page look good, read well and NOT seem cluttered. Or for figuring out the page dynamic.

...how can you people stand planning your comic so far ahead? If you know what's gonna happen, what's the fun in making it? You're just going through the motions...

I've actually gone so far as to make the first three panels of a page and then try and work out what the punchline is gonna be XD

Because the actual page never ends up exactly as the script pictured it. And often you pleasantly surprise yourself with your artistic awesomeness, if you worked at it hard enough.

I'm extremely loose. 99% of the time I never write any scripts at all and I hardly do rough sketches because it takes away all the fun of creating stories. I only have a few rough idea in my mind and I usually don't dwelt deeply how the story should flow. I just let my story flow as I draw my next page. What's really funny is that readers still do enjoy reading some of my comics despite the improper planning in some parts of the plots in my comic.

I have a loose script. I know what's going to happen, but usually I come up with the humor and sight gags on the spot.

Due East is tightly scripted, it's the only way it would work. We have very specific things we're trying to relay with the characters and the overall story. I write out the dialogue for each page then review it with my wife, we make changes and agree on the final script for each page. I prefer to get several pages of script done before I try to do any art. Personally, I like to know where things are going before we get there.

Off Hours is a little more loosely scripted but it's still scripted. Sometimes the artist will decide on some specific dialogue, especially for their own characters/actors, but we have an overall idea where the chapter is going and where it will end up.