Another one giving personal experience of dressing there and in other Muslim countries in north Africa: you can almost wear what you want (I'm sort of presuming you're not a hot pants 'n' boob tube type of woman so not even going there), and a knee length cotton skirt coupled with a cami would be alright; I'd wear the cami with a cotton scarf around my shoulders or light cardigan, good for keeping sun off, but you can slip it off when it gets too hot, walking through town for example.
Yes, wearing a camisole top and showing bra straps may get you a few more letcherous looks than a short-sleeved top would, and a wearing a short sleeve top will get more looks than a long sleeve top. A skirt and jeans or trousers may get equal amounts of letcherous looks as one shows your calves and one shows your bottom.
Long hair always turns heads, so if you wear your hair down that will get you more looks as well. If you're young and pretty you will get more looks than if you are old and/or ugly.
But if you don't look like a local woman, if it's obvious you're a tourist, then you'll get letcherous leers whatever you wear. So don't shoot yourself in the foot and cover up totally as whatever you wear you'll still be looked at, as quite simply, your face, your hair, your husband, your clothes will mark you out as different, and unless you wear a burka and cover your face you will probably be stared at.
Also being with your husband will reduce the letcherous looks; you'd find it much more prevalent if you visited with girlfriends.
However, even more so you will also be welcomed, as a visitor to the country and as a valuable source of income. Make sure you buy local products (try and get stuff made in the country and not in China - it's harder than you'd think) and spend money there to help people make a living out of the tourist industry, and you'll find you get plenty of genuine smiles.
Probably easiest for you to just find this out for yourself though...
Seriously, the only must-have item for tourism in Muslim countries is a cotton scarf to cover your shoulders for visiting mosques and other holy sites. And that's the case for Hindu, Buddhist and Catholic holy sites too, just as it is for many weddings in the UK.. (have ever you tried going in a church in Italy wearing a camisole?!)
Hope I've not gone on too much and this is helpful. Have a great time, and don't take too much from home as it's a wonderful place to shops for pashminas, scarves and fabrics in the souks..