Etiquette in Morocco is a very important aspect when visiting. The most important thing to remember is that Morocco is a Muslim country, so the local norms and customs should be respected. In practice, this translates into dressing modestly, and avoiding public consumption of alcohol and public inebriation. Taking photos of Moroccans going about their daily business is fine IF you ask for permission first.
Learning even a few phrases of Moroccan Arabic will win smiles and praise from you local hosts.
When it comes to tipping in Morocco, between 5-7% is good for restaurants- but only for good service, not as a mandatory action. At many of the upmarket restaurants in the tourist areas they will add 10% to the bill, therefore check your bill. If you don't receive good service then don't tip.
In taxis, just round up to the nearest 5 dirhams, e.g. if the taxi meter says 17, pay 20. Though often with taxi's the meter won't be working, so always ask the price or check the meter before you start your journey.