This is actually the easy bit. You might feel like an international trader as you bargain with the local manufacturers but the truth is that anyone can spend money.
You need an angle. There are some items which will always sell okay (clothes, silver rings, bindis) and there are others that will almost never sell (hammocks, precious stones, water pipes). Most things have been done to death and can now be bought wholesale back home cheaper than you’ll ever get them for.
Look in the shops before you go and get an idea of prices and what sells. Have a chat with shopkeepers who may end up buying your stuff and ask them what they might be interested in.
Keep on the lookout for fashions. About ten years ago silver snake bracelets from India could be taken back to Europe and sold for 7 times their value at a snap. Then sexy Hindu God t-shirts and tops were all the rage. Make the acquaintance of other road merchants and ask their advice.
Get to know what you’re buying. You don’t want to arrive home and find that all the clothes you bought won’t fit anyone. Or that the stones you bought were all fakes. In particular stay away from jewelry until you really know what you’re talking about. Hang around other jewelry heads and bring them tea.
If you have good taste and an artistic eye you can get your own designs made. This is a good long term way to go as you’re selling something that no one else is. In places like Bali everyone gets their own styles made up.
When you actually decide to buy something don’t get too chummy with the manufacturer/shopkeeper. He won’t give you a better price just because you’re nice to him. Be respectful but don’t believe any of the pained faces they put on as you drive the price down. They’ve seen suckers like you come and go all their lives.
Depending on where you are you’ll need to check the quality of what you buy. Silver in Thailand is almost always good; anything made in India is guaranteed to be 50% crap. They’ll replace the faulty items and half of those will be falling apart at the seams. Patience is the real commodity you need lots of here.
It’s good to support family businesses and local industries as much as possible. You don’t want to be buying stuff made in sweatshops by 8 year olds making a banana an hour. Do your best to find out where your stock comes from.