I carry my passport on me at all times. I consider it to be my lifeline.
(My hotel room had a nice safe, but I didn't use it.)
In case of an extreme emergency or evacuation, I have peace of mind to know I have my original PP, money/euro, and my credit card.
My last two International trips, l traveled by myself. What l also include in my PP is an index card or two with some basic medical info - blood type, any meds or OTC's, vitamins I may be taking, any allergy l may have, any surgery l may have had, my USA doctor's name and phone number, and family contacts.
In the event l am unable to communicate, l want emergency personnel and/or doctors to know what they're dealing with so they can treat me quickly.
I keep the index cards in the back of my PP.
l carried a Hedgren durable, small cross body with my PP, credit cards, euro, phone. That never left my body.
(My first trip, I tried a money belt. Didn't care for it. If l was to travel in between countries or a questionable area or transport, then I would use it. I stayed in Rome for two weeks each trip, so it was easier. I walked all over Rome's city centre and then some - it was fine. I stayed in a lovely hotel in the Termini neighborhood; no issues.)
I used my 14" Kipling purse/tote for everything else - to carry bottled water, other miscellaneous things, small packages while out and about in Rome.
Also, a key point is organization. I've always been organized - put your valuables, etc. back in the same place you took them out of. This minimizes any fumbling or nervousness and greatly reduces loss or misplacement of goods.