Vaccinations

Make sure you have seen a travel doctor at least 3-6months before your trip many vaccinations need to be taken over three courses with a month's gap in-between.

Remember to take your vaccination book when you travel. It may be needed as there are different types of vaccines for various diseases.

Backpack

You will need a good quality backpack for your trip. Remember your pack, should not be too large as you will have to carry it constantly. It should also not be too big as you will have problems when getting on buses and trains etc.

Along with your backpack you will also need to take along a day pack, to safely keep any valuables you are carrying, particularly on bus/train journeys.

They are also very handy to put purchases in and for general items you always like to have to hand.

Clothing

T-Shirts - 2/3 will be enough. You will get bored of wearing these very quickly if you're on a long trip. Also they will wear out and you can always find cheap replacements wherever you are in the world.

Shorts - Shorts are essential if you're going to warmer climates. Again only around 2 pairs will be fine as you do not want to overload your backpack. The best thing for men is to have swimming shorts so they can take a dip wherever you are.

Trousers - 1 or 2 pairs of lightweight trousers is recommended. They are good for the evenings and serve to protect you from mosquitoes and the chill outside. Jeans are a good idea if you're going to go to colder climates.

Swim wear – Guys should take along swimming shorts, while the girls can carry bikinis for the girls. The latter must however keep in mind that the touristy areas of South East Asia are fine for bikinis but only on the beach.

Waterproof jacket - A lightweight waterproof jacket is always recommended.

Sandals/Flip Flops/Thongs - I find that this is all I wear when I'm away as it's usually so hot. Take a couple pairs incase of breakages or if they get stolen which they tend to do in SE Asia.

Trainers - Take a good pair of trainers, if you've got a day of walking round a city or temples a nice pair of comfy trainers will be of great help.

Hiking boots - If you are going to go hiking then taking your own pair maybe beneficial. A good pair which will last in the tropical forests and monsoons will be ideal.

Towels - Take along 2 towels-one for the beach and one for showers. Try to carry lightweight ones that dry quickly. You don't want a wet towel in your backpack with all your other clothes.

Essentials

First aid Kit - A good well stocked first aid kit is essential for any trip. You never know when you may need this. Also some needles and syringes would be good , in case you need an injection.

Deet/Mosquito Spray - Keep the mosquitoes away with some repellent.

Mosquito net – This is a very important item to carry.

Toiletries - Shampoo, deodorant etc, you can buy these when you are traveling but it's good to bring some with you to start.

Other must take-alongs

Passport sized photos - when crossing borders and obtaining visas you usually always need at least 2 passport photos. Take a good supply with you.

Camera - Obviously a camera is great to take along so you can keep a memory of your trip. Also put them on your favorite social website to show off and make your friends and family jealous.

Money belt - For security its best to wear a money belt to keep your money, bank cards and passport safe.

Alarm Clock - You will need one of these to help you get up for your bus or train on time.

MP3 Player - Always good on long journeys. Try to get a lot of music on it before you go as you will get bored of your music quite quickly.

Playing Cards - Good at all times, especially when facing long journeys or rainy days.

Torch - Depending on where you go electricity might be in short supply. It also comes in handy when trying to find your way back to you hotel or to the toilet in the dead of night.

Reading books - Like with the MP3 player a book is a good way to avoid boredom on long journeys and relaxing down the beach. Once you're finished with te one you are carrying you can swap it with other backpackers you meet.