Everything that has been written in previous comments is true...... the Loft is fabulous and the hosts Monella and Andrea are great so all I am going to do is recommend places to go to and things to do.
Bologna is an amazing city and we were lucky to visit it in glorious blue sky weather. Visit as many Basilicas as you can, they are truly stunning in their size and decoration. Climb as many towers as you can, fun to do and a great sense of achievement with the views from the top of each giving a different perspective on the city.
Do the Portico walk to the Sanctuary of the Madonna Di San Luca, do it in its entirety if you are reasonably fit, allow plenty of time, wear comfortable shoes, take water. Go in the church at the top, pay to go up the tower, the view is spectacular, read up on the history before you do the walk and get up close to the painting which is at the centre of it all. There is a little bar at the bottom on the flat section of the walk which serves lovely Aperol Spritz, very welcome after the climb and descent, I had 3!
The little restaurant 50 yards from the apartment was very good, full of atmosphere and people and great food. Roxy Bar under the portico by the Two Towers serves fantastic cocktails, try the Bellini. The food streets off of Piazza Maggiore, to the left if you are standing in front of the Basilica, are great fun for eating, drinking, walking and photographs. I tried Aperol Spritz for the first time here in Bologna and its my new favourite drink so try it a few times.
Two bits of advice, ignore the graffiti, accept it and try and see it as part of the city culture. Secondly, keep your personal belongings safe preferably in a bag over your shoulder, my husbands wallet was in a zipped pocket of his jacket but was stolen by probably the person sitting behind us in an outside bar so our last afternoon was spent cancelling cards and visiting the police station!