Bargaining, especially in Southeast Asia, is an art and a skill. It requires patience with a smile blended with confidence and no, being an asshole is not confidence. When in Southeast Asia be prepared to be bombarded by people trying to sell you something. My suggestion, if you are not interested, politely smile and shake your head and keep walking. Saying “no thanks”, politely will work but it might get the person trying to talk to you. If you talk to a shopkeeper they are going to keep going and try to sell you something. If you carry a conversation, many of them are going to think this is going to be a sale (this includes taxi drivers and tuk tuk drivers). First, shop around and see how much prices are around the area. This will allow you to get a feeling of the average price. If a shopkeeper ask you what you want to pay, start low. Example, if you want a tank top, and the average US dollar price is five, I would start at two. If interested in something, politely ask how much, or you could start off really low. I suggest, first getting to know the shopkeeper, asking him/her about their day, “has everyone treated you well”, etc. Actually make a human connection with the person. Be friendly, smile and never raise your voice. Making a joke and joking around definitely can help. Do not be too nice and get taken advantage, make sure you are assertive. If you do not like something, say it. Start low and work your way up. When I negotiating, I do not try to win, I try to find a middle ground where we both can be happy. Remember that many of these shopkeepers are poor, and though you may not be rich, you are still well off compared to many of these shopkeepers. You are representing your country.