I wanted to hear a few words about travel writing. What qualities make for the most engrossing stories, especially for readers who are just sort of gauging their interest? I've read a number of articles mostly containing general advice or regarding particular conventions, and they're helpful, but I'm looking for opinions that are a little more specific and insightful, the nooks and crannies.
I would say- make it interesting for a human being, not a statistics gathering computer. Don't give the number of airports or hills, don't tell me what the currency rate is. I can find these things on Wikipedia.
Instead, give your opinion. What did you see? What did you like? What wasn't so great? Was the mountain top beautiful? But did you get ripped off on the way up by the bus driver, and you recommend others take a taxi instead? I want to know what you felt.
Feel free to recommend hotels/restaurants, as long as you don't make it look like a paid commercial. Readers will know if you are giving an honest opinion, or if you are just being paid to say good things.
Post pictures. A picture is worth a 1000 words. Rather than say the mountain was beautiful, post a picture you took of the sunset there.
Mention easy ways to travel. Is there a good public service transport service? The first thing I do before going to a new place, I find out how I can travel around. Official websites give useless info, like bus numbers. Give me info that is useful- that while there are a lot of buses, they have a poor service, and I'm better off walking to most places.
In summary: Don't repeat what is there on the official documents/websites. This information is often incorrect, out of date, or 'beautified'. In a good travel article, I find hope to read stuff the official website didn't tell me, and how the traveller on the ground felt.
I would say your question is not too open-ended, but instead that the answer is the same as most questions about interesting writing: you have to make it interesting.
What makes up the "interesting bits" can vary depending on the reader, but ultimately it will come down to taking your readers with you on the journey. As always, show, don't tell. If you find yourself describing landscapes or interactions, then you might be in trouble. But if you talk about what you experienced while in that place, your far more likely to capture your reader.
If you are writing in the first person, your audience is going to want to believe that you were there. They are going to want to know not only what you saw, but also what you touched and tasted and smelled and sensed. If you are writing in the second person (which, for travelogues, is an option), they are going to want to believe they are there. They to want to know what they are touching and tasting and smelling and sensing.
Ultimately, it comes down to the same ol' writing clichés: show, don't tell; and focus on the action (and the details around it). If you described a mountain, that's okay. If you relate your journey climbing the mountain and how the rock felt in your hand and how the thin air tasted in your mouth and felt in your lungs, that's when they are going to want to turn to the next page...
I suspect that what will be interesting depends on your target audience.
If you're targeting audiences that are looking to travel somewhere, then they'll probably want to know a bit about the history of the place, its people, details and places to go that are "off the beaten track", and so on, and less about stories. For example, I myself rarely read travel writing, except if I'm planning on going somewhere, and so I tend to look for things that tell me about where I am going, and things I can do there. If I can find somewhere that's away from the crowds of tourists, so much the better. I'm often not terribly interested in stories about the person who went there, and what they experienced.
If you're doing a piece of travel life-writing and you want to attract an audience who enjoy reading about adventures and mishaps of the writer in far-flung places and cultures, then your focus is going to be very much on your journey, the life stories you've experienced that your readership can relate to, just like in fiction writing. It's got to be personal. It may include history and details etc., but the focus is more on what you experienced at a personal level. Consider Michael Palin's TV series where he travelled around various countries, for example, which was designed more to entertain than enlighten (although it did). Or Tim Butcher's excellent "Blood River". Both of these are good examples to draw ideas from.
As others have already said, remember to adopt good fiction-writing techniques (setting, dialogue, characterisation, research) to tell your story, just as you would normally. Also remember, it can still be "true" to what you want to say, even if you have to make up some of the dialogue, or change some minor details.
Of course you can try combine both approaches to attract both types of audiences by writing your travel stories, and then including extra information for would be travellers in a sidebar, an additional post (if blogging), or something like that.