I just make cool looking areas and then connect them to other cool looking areas and slowly try and decide how they should fit together into a cool layout as I go. Sometimes I have some specific gameplay ideas I want to do, and I'll start there and design around that.

Planning everything first is a way better approach and gives much better results though... but I find it so boring to work on a level that I already know where it's going. 

I agree with Scampie. I have an additional problem where I find it hard to stay interested in a box map. It needs to look cool to maintain my interest and that's not always productive, I know, but it's how my brain works. 

These replies are very curious after reading the rock bottom frustration thread. 

I plan my map holistically, I map it out in a crappy paint program, labelling what I want where. The exact details get ironed out during the build, but I have most of the ideas in my head from the get-go.

Then as I continue I realise that my skills and my imagination don't correlate and I end up simplifying or giving up :)

As for the last question, the two are inseparable. I think "ooh gee, I'd like some zombies... I know a graveyard!" or "this is an excellent balcony, ahh, the perfect place for an ogre" 

Usually when I have a map idea in my head (sometimes a series of images, sometimes static) I just try to recreate it. If I am out of ideas, I imagine walking around the level and what areas it could connect to that would be cool. Most of the time I always think of something but some ideas just take a long time to actually create faithfully. 

I start by having the layout and items of a room or two in mind and then try to fit the lot together with a relatively good flow. Actual build starts with floors only after which I start filling in walls and architectural detail. 

If I have a very clear idea of what the map will be like, then I think of it from start to finish in one go.

However, every time I start making the map I begin changing up thinks as I go along because either it doesn't look as good as I had thought or things like the game logic and monsters aren't behaving as they should.

Then again, I am doing this as a hobby in my spare time so it's limited to how much actual mapping time I get. Mostly I just think over the ideas in my head and plan it back and forth until I have something I can be satisfied with.

When I mapped for the Quake 3: Areners I often drew elaborate maps with paths on paper to get the planning right with regards to the items. For Quake 2 I've only done it once for one map. The rest has become muscle memory now. 

 

Particularly regarding functional or pseudo-functional architecture. I often have a vision in my head of what a cool scene would be, but it only becomes clear to me what goes where and how things fit together as I'm in the process of building - which gets longer and longer as areas get larger and more complex. I gave up planning maps years ago. Yet even if I didn't consciously plan anything, I get this strange feeling when I've built something in a way that finally seems logically "finished" layout-wise (if not detail-wise, since I do tend to sacrifice detail for scale). Lord Dunsany said in writing his stories it was like remembering lands he wandered in forgotten dreams and that's the best way I can express it. Most of my maps don't display any obvious sense of pseudo-functional place, but I'm hoping future ones still may. I think if the mapper has an idea in mind, the player will benefit from that in terms of atmospheric experience, even if the communication of that idea is unconscious. I can think of some great maps like mfx's ikwhite map for example, that do just that. 

Said the best maps are those that look like they can continue existing without the presence of the player.

I think he's on here but I forgot his name. sorry to you, but that was well spoken and something I always keep in mind when I map. 

In DM detailing is really hard, however, because now you need thematic excuses that fit exactly to block geometry. 

I have an overall idea which is usually just a theme or a cool gimmick. Then I try to think of layouts in my head. I still only go room by room with light details along the way. What I have in my head is rarely what appears in the editor though! 

I try to get a holistic overall view of my map for consistency of theme.

Individual rooms, however I vary the mechanics or theme slightly to retain interest. I Blend different rooms together through shared textures (or similar colours). 

...is a shitshow. I try and map things out ahead of time on paper but it's just a blueprint that can change dramatically. My most recent map started with only the floors so I could visualize the layout and scale. I still made the level way too big. Still learning how to be efficient - long way to go. 

I love some graph paper sketches. Most of the time I end up just doing stream of conscious mapping and everything changes. Like others I have the idea in my head first.

Lately, I've been attempting planning out more thoroughly the idea in my head. Attempting.