Tips for a first timer ... Hmmm
Immigration at airports (and probably at sea ports) into Morocco is slow and tedious. I have entered via Rabat and Casablanca and they are similar, although Rabat better because its quite a small airport.
When shopping HAGGLE! Best not to buy on your first visit to a shop. Go to shop A, haggle, see what the pricing and selection is like (for instance, for a carved fossilized dish), then go to another, repeat. If you feel like buying, don't go back to either, as they will probably remember you and know you are interested. Go to a third shop, find the same or similar thing, haggle politely but determinedly and you will probably end up paying much more than you should, but it will probably be a cheap-ish price in absolute terms.
If you go on tour with a local guide (eg round the Marrakech souq), he will probably take you to a place where the quality is 'guaranteed', but there is no price negotiation (places selling 'real' pashmina are often like this). Again, try to do some shopping / haggling before this to see what the quality / prices really are like. But if you like what you see, ask politely if they will give you a discount, but if the answer is no, just see if you think its worth it. Our guide took us to the inevitable carpet place, which we said up front we didn't want to do. We just walked straight out again and the guide came out a few minutes later.
Don't drink water from taps or jugs or juices at market stalls or roadside places, unless you see then squeeze the juice from the fruit in front of you, every time. Bottled water only. Fresh orange juice should be plentiful and cheap.
You are in a tour group, so probably won't affect you, but taxis, especially at airports are huge rip-offs. Usually all taxis there run by one guy, and they will charge the same, all a HUGE amount (ie maybe 25 euros minimum), with no negotiation, unless you have some French and have time to argue in the sun.
Food is pretty good, especially at places obviously set up for the tourists but on work trips I've been to plenty of local, out in the boonies café type places and never suffered any ill effects. Tomato/lettuce and onion salad in a small bowl is a popular starter. Must try a tagine or 3, hard to tell if its going to be a good one or not, but should be bubbling hot in front of you, with good meat and lots of colourful veg.
Again, with a tour you are probably be OK, but traffic can be awful anywhere, but especially in Casablanca. If you think you should leave for the airport 2 hours before a flight, leave 3 hours before.
Personal security - generally OK, with usual common sense stuff. Definitely less good at night. I (middle aged male) have walked around the tourist parts of Marrakech and Casablanca at night, where there were plenty of people about. Lots of people were hissing at us - offering 'hash' (-ish).
If you have a little French, that helps a lot. English is most people's third language.
I've seen tourists and even local ladies wear T shirts and short-sh pants - Morocco is quite a liberal country, but I would suggest to ladies not to push your luck - you might go into a shop where the owner is conservative and you might be shunned. I'm not talking about wearing scarves & long trousers, just don't 'let it all hang out'
.
Hope that helps.