I cannot say much about it, due to the fact I'm going to be selling it. However, I can give a little of an idea of what I'm working on.
I was first contacted by AdventureAWeek.com about 2 months after I dropped out of RPG Superstar due to my screw-ups. They were curious if I would be willing to write an adventure for them. After many trials and tribulations (mostly me trying to remember how 3.5 rules worked and creating 3.5 copies of creatures) I finished the adventure -named redacted. It was centered around a small town called Iversdam and the nearby forest, owned by a benevolent druid. But the druid was driven out by a mad nymph named Daphne. It was a short little adventure, but I had fun with it, and it got a good review from one of the major 3rd party reviewers.
However, I re-read it later and was...irritated. I found that several RP xp rewards that I meant to put in hadn't been (my fault), and that I hadn't added values to several pieces of treasure, and so on. I contacted AAW and mentioned I had these fixes, and that I'd come up with a series of ideas for new adventures, but that having to write up 3.5 stats was constraining my design decisions somewhat. They responded that, instead of just updating it, why not re-write and expand it? Thus I came to the decision to write an adventure path, as I brainstormed how to tie much more than just those areas together.
My flaw, such as it is, is that I don't think in the terms of single, stand-alone adventures. I'm a fan of epic adventure arcs. And often I will design an entire region around the adventure arc. Currently I have a 19 page (unfinished) document that's a gazetteer of the region, with campaign traits, a number of racial traits, local deities in the AP, a new feat and modified feat, and two prestige classes tied to the region. More will be added, but it, at times, is a case of fatigue writing just that. My intended AP was going to run from 2nd level (1st is too squishy) to 15th, but it may end up higher level, as with what I've designed so far, the PCs should be at least 9th by the end of Part 3. Well, if they take on everything, at least.
I suppose I want to add a bit of my design philosophy on adventure building as well, though.
Personally, I believe that adventuring should be a challenge. If a fight isn't APL+1 minimum, the party will walk over it (there are exceptions to this). Due to this, my encounters tend to average APL+2. This tends to mean that PCs may die more easily, but for the style of play I tend toward, it is perfect, because the adventures feel more epic overall. This does not, however, mean that every single opponent should be this powerful. I have, in places, thrown a pile of CR 1/4 creatures into an area level 4-5 PCs are going into, because it makes sense for them to be there. I expect them to die. The PCs may feel like gods amongst mortals when they do it, or feel horrified. That is their problem. The area needs to feel right to me, not necessarily everyone else.
The other aspect, and the one at which I'm told I excel, is on creating NPCs. In my opinion, if you create a two-dimensional NPC for a single purpose, you're doing it wrong. Every NPC has their own hopes, dreams, and motivations. If I put an NPC into an adventure or game, at the very least I know what their goal is. That goal may be as simple as the shopkeeper wanting to move into the upper district, but every last one of them needs to have their own personality and goal. Even if I don't write down any information other than their name, I consider it. For instance, in one of my adventures I wrote up a sorcerer. Low level, odd skill selection, no real gear to speak of on her. She owns a house in a major city of the region, and spent most of her WBL on it. She has a small library of arcane lore. She's a self-taught scholar, and her goal is to create a prestige class. Not saying what, specifically, because she's in my adventure, but that's who and what she is. I through her in at a whim, and after about 30 seconds came up with her personality and goals.
Anyway...my verbose, rambling response.