Aix en Provemce

I don't mean to be flippant but what kind of advice do you want? About where to look for accommodations? How to get around? Where to eat? What to see and do? Please expand on your inquiry.

Buy and wear your money belt so you don't get pick pockets.
Avoid large groups in public demonstrations.
Avoid getting drunk and walking home alone late at night.
Say Bonjour and Bonsoir when entering store and restaurants.
Learn some basic French before you go.

What takes you to Aix midwinter? Are you taking classes at the University? How exciting to be there “hors saison”. I’ve spent a lot of time in Aix and love it.

My first thought is bring rain gear. Some of the heaviest rainstorms I’ve ever experienced were in this region in February.

Transportation...bring your International Driving Permit because you will probably want to rent a car to explore the countryside and coast. (Permit is rarely requested when you rent, but helpful if there’s an accident). Public transportation is more local commuter focused in winter.

Check out the numerous cultural events and performances, and book early. The Aixois buy subscriptions and are avid theatre, dance and concert goers.

Take advantage of the local TGV station routes to explore further afield.

Let us know if this is the type of local knowledge you’re looking for?

"Permit is rarely requested when you rent, but helpful if there’s an accident."

In France an IDP is required. I've never been asked for it at the rental counter, but not having it if you're in an accident or other roadside event would cause you major problems.

"Buy and wear your money belt so you don't get pick pockets."
Why would you need that? Would you wear one at home all the time (Well, I see you're from Chicago. Maybe you feel you need to)?

I don't know about winter, but I was targeted by a trio of pickpockets on the local train along the Rivkera in May, so I think caution is warranted. Personally, I only use a money belt when I'm changing hotels. On other days things like extra ATM and credit cards remain locked in my suitcase in my hotel room.

Though the air looks clear and bright, it can be very cold when the Mistral wind blows, which is about every third day in February and March. Be sure you bring hat, scarf, wool socks and gloves, as well as sunglasses and sun screen.
If you are a hiker/walker, the terrain is very rocky. You'll need high-top hiking boots and at least one pole. There are sports stores in the area.
My favorite readings for the area: M.F.K. Fisher's Two Towns in Provence, about her life in Aix and in Marseille at different periods of her life. Some of what she saw and experienced is gone, while other things have stayed the same. Second, Marcel Pagnol's books give a taste of Provence a century ago. They might be available in whichever language(s) you read at a local university library, or you may be able to find the movies made from his plays.
Lucky you and bon séjour.

What advice do you have?

It's an interesting question, pregnant with possible responses.

If only we readers had some inkling what topic(s) you had in mind when you wrote it... what a wonderful world that would be!

I never wear a money belt but not everyone is street smart

Aix en Provence is on my bucket list for a month in offseason... I love that you posted this and I am particularly taking note of the reading suggestions.

Not pertaining to Aix, but for my solo travel in general, I stick to a system that keeps my back up financial documents (CC, money, etc) separate from the items I use during each day. I keep the same system for the entire trip. This keeps me from losing all my material at once. It's on me in transport and in my hotel once I've arrived (or whatever). Personally, I don't think it is the money belt so much as a definite system, although I will use a moneybelt in transit depending on my system for a particular trip. In other words, know your system and stick to it.

I look forward to reading more suggestions and about your trip!

Find a list and map of all the fountains; try and find them all. The markets are great.