I can help out with this one. I lived in Morocco for awhile.
If you're on a tour, great. But if not, GET THE HELL OUT OF TANGIER THE MINUTE YOU ARRIVE. Tangier is a festering cesspool of touts and thieves. To quote Obi Wan Kenobi, "You will never find a more wretched hive of scum and villany."
Have a map IN HAND leading you from the port to the train station (it's too far to walk), and use that to make sure your taxi driver takes you to the station and does not lead you into the medina. You'll pay some stiff extortion if you get stuck in the Tangier medina.
Once you get to the station, Meknes, Rabat, Agadir, Safi and (my favorite) Marrakech are all short train trips away.
You will get the occasional tout in Agadir, and some more leading to the Jamal el Fna in Marrakech. They're easy to deal with. Treat them like you would a timeshare OPC -- ignore them, don't engage them in conversation, and walk directly to wherever it is you're going. If you don't know where you're going, walk as if you do. We found that keeping an animated, running conversation was a useful ploy -- the touts couldn't get a word in edgewise.
If the touts get to be too much for you, there's a police officer with a machine gun standing on the corner, every few blocks. The touts won't get within 100 meters of the cops.
The touts are (for the most part) harmless. Here's a link:
http://www.buten.net/max/Morocco/touts.htm
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As for shopping, you will find 1,000 things you want to buy at the craft stalls in Morocco. Their leather and brass work is simply amazing.
Everything you've read about haggling in Morocco is bogus. Do not offer the shopkeep half of what he asks -- you'll be paying 10x too much. Here's how to do it. Haggle the shopkeep down as far as you can. Leave the store a couple times in order to get the absolute best price. (1/10th the original asking price is fairly reasonable.)
Then, LEAVE. Go next door to the next shopkeep who is selling the EXACT SAME STUFF, and tell him, "The guy next door will sell me that brass pitcher for 30 dirhams. What will YOU sell it for in order to get me to buy it from you instead of him?"
Eventually, you'll get the hang of "power haggling" in Morocco.
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I don't know how long you're staying, but one of our favorite activities was to walk into the medina, get hopelessly lost, and spend all day finding our way out. We saw the coolest stuff that way -- the actual artisans who make all that stuff you want to buy, for instance. Sometimes they'll sell it to you.
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Sunglasses and T-shirts with english stuff on them make great currency. In fact, I'd pack all the clothes I want to give away, and trade it with the locals.
The street food tastes excellent. (Their orange juice is a thing of wonder.) I did get really sick once, though.
Speaking of which, bring some toilet paper over from Gibraltar. YOU ARE GOING TO NEED IT.
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Finally, without a doubt, try to befriend a local and get an invite for lunch or dinner in their Riad. (Took me about a month before I could find someone trustworthy, though. Might not happen for you.)
All those dingy buildings you walk past in the medinas of the cities of Morocco are drop-dead gorgeous on the inside. Try hard to get a look inside one.
Edit - Learn some French if you don't already speak it. You'll need it for directions. The more Arabic you learn, the better your time in Morocco will be. As goofy as it sounds, rent "Ishtar" and watch it.
PS -- My wife cracked our tagine. Any chance you'd send one to Las Vegas?