Most foreigners who visit Laos are terrible at bargaining, which isn't their fault because bargaining simply does not play much of a role in their everyday transactions in their country except for large purchases like buying a car and a house. Most of them aren't used to it and they are certainly not used to disputing over small everyday items.
In Laos, you can't bargain for everything but you will be able to bargain for most things, even if the item has a price tag it doesn't hurt to bargain.
Some places have fixed prices and you are not expected to bargain such as in a restaurant, night club, mini mart, internet cafe, cinema and purchasing a bus ticket. Normally you can't bargain for a short-term stay in a hotel and guest house, but you can negotiate a lower price if you plan to stay with them for more than two weeks.
Bargaining is a necessity while shopping in Laos, since many sellers purposely put their items at high prices because they know that you will attempt to bargain. Now all you have to do is make sure you bargain with skill so you can get the price you want, or even lower.
Take some time to ask around, find some local Lao people who can give you an idea of a good price of the item that you want to buy, so that when you start to bargain with the seller, you will have an idea of a base price to work around, and you can try to negotiate down (or close) to that price.
A trick is you have to pretend that you're willing to walk away. Often you'll find that by simply showing a lack of interest and willingness to avoid the transaction the price will be lowered, without any need for specific bargaining on your part. Don't wear flashy outfits or anything that suggests you are a wealthy person. A t-shirt and shorts will do in Laos. And please, don't be stingy and argue over 1,000 kips (10 cents).
The main thing to keep in mind when you're in a Laos is that your status as a foreigner will usually label you as rich to Lao locals, even if it doesn't seem that way to you. If you don't want to get charged double, then you'll have to get used to the idea of bargaining. This is a key idea in the overall strategy of discount travel in Laos. A lot of small things that when applied together result in big savings for you, and your holiday will be more enjoyable.