Hi sqs,
I will share my experiences. Even though my trips to Rome have been in December -- a couple of weeks. (Other trips to Italy have been in the Autumn months -- warmer and different clothing.)
Perhaps something will stand out to you, and you can customize your own travel wardrobe.
I wore/brought black pants -- wore one on plane, packed a pair in carry on and packed another pair in checked luggage.
I plan a coordinated 'look' -- tonal, monochromatic, or muted. (I prefer Black, Cream/Ivory, Grey, Brown, Purple for winter months of travel.) I layer my V-neck, tunic-style sweaters with a spaghetti-strap (color coordinated) tank underneath.
Play with some outfits before your trip. Mixing and matching and coordinating will be "your friend."
I also bring a couple of scarves to change the look a bit. Wearing a coat out and about all day in colder weather, no one will see your outfit much.
I discovered this adorable little shop that sold "Made In Italy" wool scarves and other clothing. Very inexpensive! Most of their clothing were pretty muted tones and ivory. The store was jam packed the few times I went. It is in the Campo de' Fiori neighborhood. (If interested, I can give you the addy)
I wore a knee-length, "thinner" puffer coat with a detachable hood (saves for carrying an umbrella) My last trip to Rome saw a few very warm and unseasonable temps -- 70 degrees. So, weather can change. The year before saw very cold and windy low temps during the day and night.
What I noticed of a lot of women is that they wore fitted jeans or some type of trouser or slacks -- usually a dark bottom.
A lot of women had on puffer coats -- either a brown, champagne or cream color. I even saw them hanging in store front windows on display.
For shoe wear, I saw women with beautiful, leather "oxford style" tie shoes, loafers or some type of ankle boot. I may have seen one or two with knee-length boots. Teens usually wore some type of athletic shoe -- decorated and with a higher sole.
Many also carried a very large, satchel style hand bag.
Travelers wore athletic style shoes, boots or shoes. I wore & brought extra pair of cute black shoes. I saw many who had on fitted clothes and fitted jackets. Italians usually prefer that mode of style compared to maybe what we see in America.
I leave my leather bags at home -- they will become too heavy to carry after a while. I use one of my Kipling bags -- tote or satchel style -- black. They can be converted to cross-body when needed. It is also good for putting small packages, snacks, water, etc. to keep it all in one place.
I organize everything in my bag -- putting things back in the same spot for less confusion and fuss.
I also use a mini Hedgren cross-body (about 8") to carry my Passport, Phone, extra money, cards, and other pertinent information. It is not noticeable under my coat. Of course, during summer travel for some, it would be obvious.
I never put my bag on a table or on the back of a chair; even in a restaurant.
Even if you visited Boston, I would advise this: Keep a big city awareness. Rome is relatively safe. I had no issues. And, there are people who do help out if you get turned around or lost.
Try to focus on a known landmark as your point of direction. Take your hotel card or address with you. If you are staying in a major neighborhood such as Termini, Navona, Campo de' Fiori, Spanish Steps, etc. -- everyone knows where they are, and you can go from there if you get sidetracked.
I stayed in the Termini area my last two trips and am doing so again. I love the walk around Rome. You can see something different every day, every minute despite walking the same route.
Rome is an outside walking museum. Around every corner is a surprise. The city is beautiful, awe-inspiring, mesmerizing, crazy busy and fun. I love it.
Hope you have fun.