Before boarding ensure that you are not getting a private vehicle and negotiate the price beforehand. A knowledge of Thai is helpful. Seelor means four wheels whilst songtaew means two rows of seats. Tuk Tuk's should only be used for trips around the city and visitors should be warned about the many scams operated by some of the drivers. Under no circumstances should you arrange a trip to the craft factories with a tuk tuk driver as they will often take you to the shops that proffer the highest commissions, and guess who will be paying extra for the goods.
Strong negotiations are crucial before boarding a tuk tuk.
Rates start at 20 Baht for a very short trip but you will be lucky to get such a low price. If you see any real taxi cabs in the North you can rest assured that they we hired from Bangkok by wealthy visitors. Metered taxi's are not yet available in any city in Northern Thailand. The touts outside hotel lobbies and guest house's are unlicensed and should be avoided at all costs. The taxi's at the airport are, however licensed, and the reasonable 80 Baht into Chiang Mai town is a good deal.