A am speaking about the souk, the market behind Jemaa El Fna square. The things below are very obvious:

1. It is the biggest market I have seen in Marrakesh. And many souvenirs are really worth and remind about Morocco.

2. The first prices are as 1.5-2 times more as real prices to buy.
3. Do not argue, do not shout, do not rush. Nobody likes it. :)
4. There is a common rule that 'if you have spoke about the price, you should buy it'. Maybe, it is a common rule for Arabic markets, but it is just a trick for tourists here.
5. The same with the rule 'not to cheat with food'. They can cheat you here sometimes. Too many reach tourists.
6. If you ask local people about real prices, they can support the seller.
7. Do not be too clever bastards, yeah? I saw some group of tourists trying to bargain for fresh orange juice whereas the price was printed above and it was tiny (4 dirhams for a big glass of ambrosia).

Oh, the last advise. I thought about that many times: please, do not look like you have returned from a deadly fight, with cold and haughty eyes. It is your vacancies and the people around is friendly. :)