Whilst travelling there some things which I wish I had bought with me, stuff which I wish I left behind and so fourth so below are some things which I think you should pack and additional tips.
1. Pack an extension lead - Some hostels may have a couple of plug sockets, so when there's about 10 of you in one room life's easier with some additional plug sockets.
2. Passport pictures - When applying for visas you need passport pictures, it's just very handy to have.
3. Don't bother with miniatures - You'll end up spending more money, my friend and I would just buy one normal size bottle shampoo/toothpaste and carry it between us. Money was scarce.
4. If you can get wheels on your back pack then do - I didn't have a wheely backpack but Nikki did, people helped her a lot more than me. Everyone carried her bag for her where I was always carrying it mine on my back, hers had bloody wheels! I didn't loose any weight or got fitter by this. So get some wheels.
5. Get a go pro - If there's one thing I wish I had on this trip it's a GoPro, I carried my massive DSLR but it's heavy, big and not waterproof.
6. Leggings - Screw the harem pants, they are fucking ugly and leggings last longer, more versatile and generally less offencive.
7. J Pillow - You're travelling a lot and always have a coach or plane journey round a corner, you need to invest in a good pillow. I wish I'd known about the J pillow before hand because they are so much better than the C shaped ones.
8. Deet - I got bitten to shit, and it hurts. Opt for the deet 100% that does the shit. Don't listen to any hippy that bangs on about how bad it is for your skin. Because it's worse when you have about 50 red itchy splurges all over your body which wake you up at night because they are fucking irritatingly itchy and sore.
9. Anthisan - That shit that gets rid of the bites, you might still get bitten. That one time you forget to spray on the deet, it's a bugger. So make sure you have the cream to heal that pain.
10. Antihistamins - For the time when you have a really bad allergic reaction. For some reason in New Zealand I mysteriously had the worst allergic reaction ever, the cause is still unknown. I had to take antihistamines for a month to make sure it didn't make a surprise appearance. Also they help with bites.
12. Socks - There are dirty places, there are cold places and there are places that only give you a pillow to sleep with.
13. A giant square of fabric - I call this a sarong, some call it a blanket, some call it a scarf and perfect if you're visiting temples. Therefore extremely multifunctional.
14. US dollars - In asia when paying for shit like visas they lurve (require) the US dollar. Will work out cheaper compared to any other currency.
15. Those giant clip things - You know the type that abseiling people kinda have or trekkers have to clip their water bottle to your rucksack. Well they are super useful when all your stuff doesn't fit in your bag.
I didn't advise all the obvious ones because you can figure out that yourself. Those are my top tips. Enjoy.