Tequila Sunrise said:
1. Do you prefer short- ...
2. Are you largely attracted to classic dungeon-delve adventures, intrigue-investigative adventures or some other type?
3. How strictly do you expect the adventure's makeup to match standard d&d? ...
1) Short adventures are best. I prefer adventures that are designed to be run in a session or two. Longer adventures tend to lose the players, unfortunately.
If it is a longer adventure, it needs to be one with an overall plot that has the details broken up into reasonable "chapters". I can then run the chapters as a session each, intersperse other things as my players wander off track to things that interest them, but still maintain an overall plot. One of my favorite Shadowrun adventures to run was one where the first three chapters all seemed unconnected, until you got to the fourth chapter and it tied everything together; then you moved on into the fifth chapter to wrap everything up. You were encouraged to run other things between the first three chapters.
2) I like a good intrigue or investigation adventure when I look at a module. If it's a dungeon-delve, it has to have some very interesting or unique bits to attract my attention. I can write dungeons easily; coming up with an intrigue that's good enough to surprise me so I know I can use it to surprise my players, that's the hard part.
3) I prefer an adventure that isn't too strictly attached to core rules. I hate it when an adventure assumes that to finish it (or understand the mystery) you have to have knowledge of or access to certain spells or magic items.
Of course, you don't want to get too far from the core if you're planning on selling the adventure outside of your setting. I've seen adventures designed for a particular setting that were so immersed in that setting that they were basically impossible to run anywhere else and still have them make sense. I can find a way to work a tribe of lawful barbarians in. Trying to shoehorn in an entire country is much harder.
My other comment for adventure writing is that the blurb should be GOOD. I won't bother looking through an adventure unless the blurb catches my attention. (And I won't even consider some of the adventures I've seen that have no blurb at all.) The blurb shouldn't give away the plot or be anything that the player's couldn't see, because they use the same online or FLGS that I do, but it should draw me in. Think of it like the back of a movie box. You want it to grab my attention so I rent/buy the movie without giving away the ending.
The final component for me is pricing. Too many adventures are priced at the point where I look at it and go, "Nah, it's more worthwhile for me to save the money and spend time writing my own adventure." I don't think they should all be $2 or something similar, but I also don't think that paying $15 for a module that will only last one gaming session is cost efficient.