Have you ever been traveling and took many pictures? Have you ever came back and look and you pictures to find out they were all blurry and ugly? This used to happen to me all the time. I'd preview my images in the little LCD screen and then when I downloaded them onto my computer I'd notice that they were all blurred and not sharp at all. Many different factors come to play when taking travel photos.
When you are taking pictures during travel you will most likely not be able to have the precise control over your image as usual. You will not be able to control the weather conditions, the lighting, or anything really. The best way to work around this is to be prepared and flexible in how you take your photos.
One of the best ways to be prepared for taking photos in a foreign location you haven't been to is to research that area somewhat. Find out what the weather conditions will be like. Find out about events and when streets will be filled with people and eerily empty. Also, be sure to know how their weather is like during certain times of the year. Will there be mist? Will it moisten your lens requiring constant cleaning? Will there be a very bright sun that will require UV filters and hoods? If you wait till you get there you may very well end up spending lots of money buying equipment and it may not even be available.
Also, be sure to know everything that is around where you are going. Maybe there is a great underground city that you never even would've known about without researching. Some places have great wildlife areas a little away from big cities that you can go to and take pictures of.
Always be prepared for the weather. Especially if you are going to the equator areas where it will rain without any warning. I remember when I went to Cancun it was always just suddenly raining and still hot. I still took pictures and ended up with some very nice shots. Be sure not to use the flash when it is raining or snowing. This will make really ugly "orbs" as the ghost "experts" like to call them thinking they're ghosts.