Flattery always works. I’ve have made contact with alumni of where I studied ID, who have gone on to have international careers, by emailing them and asking their advice about their careers. Everyone likes being asked about their work.
I’ve arranged studio visits by contacting people on this forum, by pretty much following Yo’s advice. I didn’t bring food though but I did buy coffee. It did take some time to organise- people are busy so the visit will be when they are free, it might take a few weeks.
I also would bring portfolio/ models/ pieces with you, even if it’s just the webpage ready to be shown on your phone. I recently arranged a local studio visit, which I set up as an informal look around, so I expected it to be casual, and it was more like a job interview, which I wasn’t quite prepared for. I didn’t have paper portfolio with me but I had stuff to show on my phone as well as by chance some prototypes I’d been working on in my bag. I suppose the lesson is be prepared.
On the downside, I have organised a visit in another city weeks in advance, and when I got there, the day before the visit was due, it was cancelled. You need to be prepared for this and be gracious and take it on the chin, but it is a p.i.t.a.