#2: You Don't Check A Country's Entry Requirements

This is imperative when planning a trip. It's not just your passport you'll need to bring – which, by the way, you should check to ensure is not expired and has the necessary amount of empty visa pages – but possibly visas, medical records or vaccinations. For example, travelers are not permitted to enter the country of Ghana in Africa without getting a yellow fever vaccine. To prove you got the shot, you will need to carry a signed yellow card given to you by your travel doctor. Likewise, entry requirements vary for citizens of different countries. For instance, in countries like Brazil and Bolivia, it is not necessary for Europeans to get a visa, while it is for U.S. citizens.

To ensure you have the proper entry requirements for the country you're going to, first make an appointment with a travel doctor to get the necessary medical attention. You should also visit the U.S. Department of State's International Travel website to get up-to-date information on entry requirements.

#3: You Ignore Signs Of Travel Fatigue

When on vacation, travel fatigue is no laughing matter. If you begin to feel tired, cranky or just couldn't care less about the trip anymore, that's when it's time to take action. Book a hotel, get a massage, call a friend or family member from home, write in your journal, exercise and do whatever it takes to get yourself in the right mindset again. If you don't, you'll miss out on really making the most of your trip. Click here for a detailed list of ways to deal with travel fatigue.

#4: You Focus Too Much On Things Going Perfectly

Before embarking on a trip, you should tell yourself right from the start that not everything is going to go smoothly. Things will most likely go wrong, and that's okay; it's all part of the travel experience. You're going to miss trains, electronics will break, you'll get ripped off, tours won't run smoothly – it happens. Instead, when things go wrong, try to look at the bright side, or at least realize in the grand scheme of things it isn't a big deal. When I was in the Galapagos Islands, I let the dive instructor borrow my camera, forgetting to tell him it couldn't go lower than 10 feet of water. Needless to say, it didn't work so well, or at all, when I got back on the boat. He apologized profusely, but I just laughed and told him I hoped he at least got some great shots. Not that I wasn't upset about the loss of my $300 camera, but it didn't change the fact that I was still exploring one of the most beautiful locations in the world.

#5: You Let Bad Weather Keep You From Exploring

Just because it's raining doesn't mean your trip needs to be put on pause. If it's something you really want to do and would still be worthwhile, do it anyway. Furthermore, you could also revise your trip itinerary to include some indoor activities, and some outdoor activities that don't require viewpoints or slippery terrain.

During a trip to Banos, Ecuador, it rained almost everyday I was there. While I had planned to bike down a volcano and hike to the town's viewpoint, those plans didn't quite make sense with the weather. However, that didn't mean I was staying indoors. I simply changed my itinerary to include adventure activities that went well with rain – canyoning, rafting and relaxing in the natural hot springs. Likewise, the one excursion I had really wanted to do, a two-day tour to the Amazon Jungle, I did anyway. Despite some rain, it ended up being really fun.

#6: You Try To Smuggle Drugs Or Other Illegal Substances

Think bringing back opium from Asia or cocaine from Colombia sounds like a good idea? Think again. Not only will you ruin your vacation, you'll most likely ruin your life. Moreover, bringing back less serious but also illegal items, like coral from the Great Barrier Reef or baby tortoises from the Galapagos Islands, can leave you with heavy fines and possibly jail time.

The solution to this ordeal is simple – just don't do it.

#7: You Disrespect Local Culture

One of the best parts of traveling is learning about different cultures. Even if something is different from what you're used to, or if you don't agree with a certain belief, at least respect it. Not only will you save yourself potential conflict – and possible punishment, depending on the level of disrespect – you may find yourself having an eye-opening experience.

#8: You Choose A Bad Travel Partner

Ending up with a travel partner from hell is never fun, and can be detrimental to your trip. Don't just assume the person you go to happy hour with on Friday or sit across from at work will be fun to travel with. There are certain questions you should ask before embarking on a trip together. How thoroughly do they need the itinerary planned out? What is their budget? Do they like to relax, or are they more of an adventure traveler? Do they prefer staying in hostels, or do they enjoy luxury travel? How deeply do they wish to immerse themselves in the culture you're visiting?

If you're answers don't align, you should find a new travel buddy, or think about traveling solo.

#9: You Don't Interact With New People

If you're traveling with other people, you've hopefully chosen travel partners you get along with. That being said, you should still open yourself up meeting new people, especially locals. You may not necessarily "ruin" your vacation by not doing this, but you will limit it. Befriending locals will not only give you cultural insight, it can also help take you off-the-beaten path to find new sites that aren't in your guidebook. This also works with meeting other travelers, who may be able to give you tips on the destination. Likewise, there have been many times becoming friends with locals has helped me to get good deals on tours and transportation.

To help meet other people, you can use a websites like Couchsurfing or Tripping, where you can reach out to locals and other travelers to meet up. Furthermore, going to local hangouts or befriending tour guides are other ways to make new connections.

#10: You Go Way Over Your Budget

Going way over your budget can be detrimental, and can cause a lot of anxiety during the trip. Just because you're traveling, doesn't mean when you get home the bills will have disappeared. If you notice you're consistently going over your budget, re-evaluate what you're doing. Start keeping a journal of your purchases, so you become more accountable for what you spend. In addition, begin taking advantage of free activities, do more walking and take fewer taxis, dine in cheaper local restaurants and look for hostels and inexpensive hotels and guesthouses – doing these things can help get you back on track. By the same token, if you know you're not good at sticking to an allowance, you may want to consider traveling to a budget-friendly country.

#11: You Don't Keep Yourself Healthy

While you're going to want to explore the nightlife, and your sleep schedule may suffer, it's important to keep yourself healthy to be at your best for exploring your destination. When I was in Mancora, Peru, I neglected to reapply sunscreen when lying by the pool. It only took about four hours before I had huge blisters on my legs. By that night, I had a fever and was vomiting. I lay in bed for three entire days, trying to re-hydrate and sleep off the pain. Don't be stupid, and don't stretch yourself too far. Get a decent amount of sleep, drink a lot of water, eat right, stay active, wear sunscreen and take precautions when doing adventurous activities.

#12: You Obsess About Staying Under Your Budget

While sticking to your budget is important, it's also important not to let the financial stress ruin your trip. You need to be able to have fun, while not fretting over every penny you spend. Give yourself a budget that's lower than what you can actually spend, so that if you go a bit over you won't be losing sleep over it. Also, arm yourself with as many budget-travel tips as possible, so you're already in the right mindset. You may also want to think about putting a certain amount of money somewhere where you won't have access to it while away, so it will be there when you get home.