I'll start off with a couple of my favorite tips to overcome writers block, and will add to this list as others post their favorite tricks (with proper credit of course!).......by keeping this post at the top of this forum, it should make it easy to find and peruse whenever you're stuck and need ideas.
As any writer can tell you, it's always helpful to get away from your desk/journal/computer and clear your mind. Take a walk, exercise, go shopping - just getting out and getting fresh air often helps. But when it doesn't, try some of these tips:
1. Google is your friend! Set up a Google Alert for the topics you wish to write about - keep it fairly specific so you'll get the most relevant results (you might try searching both Google and Google News on a few words and phrases first in order to refine your list). For example, if you like to write about a particular destination (Miami Beach"), set up an alert for that. Keep in mind that in your daily Google Alert email you'll likely see some irrelevant information, but that's one of the downsides of the internet - there is so much information out there that it can be hard to find exactly what you want. However, you'll see enough interesting and relevant information that some of it should spark inspiration.
2. Review your old travel journals to see if there was a particular train of thought or idea that you never followed through on - perhaps you wrote a wonderful article about your last trip to Paris, but forgot to write the follow up piece on that wonderful little restaurant you discovered and the marvelous evening you had chatting with the owner/chef.....sometimes sparking an old memory can spark inspiration too.
3. Look through your old travel photos - it might be that jogging a memory there will inspired you to write about whatever happened at that particular moment in time when you took the photo (another good reason to print your best photos as soon as you return from a trip and note on the back the date, time, the names any people that are in the photo, and any other notes about what you were doing then).
4. Read - travel magazines, travel blogs, a good Travel Writing Book. The idea is not to copy anyone else's work, but to try to find something that lights a fire in you - it might be reading about a destination, about which you know something different than the author of that article.
5. Get out and travel! Nothing sparks inspiration more than new experiences - go somewhere you've never been before (whether it's close to home or far doesn't matter), or somewhere you have been but try to see it through someone else's eyes - a fresh perspective and you might learn something new!
Good luck - and share your own tips!