Sometimes, it just amounts to being in the right place at the right time. During my first trip to Paris, i stopped for lunch at a small restaurant and ate my meal outside. The owner/chef/waiter started extended conversations with me when he started serving me and we ended up talking about his travels and mine through out my whole meal. I went back a couple of nights later for dinner, arriving a few minutes before they opened. The workers were all out on the sidewalk talking and when he saw me, he called out, hello, Brenda. I commented that i just realized i was a little early for my reservation and that i would walk around, no rush. He insisted i come on in, gave me a free glass of wine, and brought out his CDs and asked me to pick the dining music for the evening.
Another time in Belgium, i stopped briefly into a souvenir shop and the older gentlemen began talking with me and we talked for about 30 minutes.
I think sometimes people can tell if you are one who would like to talk by your first couple of interactions. After saying bonjour, some folks just proceed to ignore the proprietors. If you speak as you walk around and ask how their day is going, or how they are, they know you are open for conversation.
People sit so close at cafes in Paris, I nearly always end up in a discussion with the travelers or locals who happen to be sitting next to me. I have met people you were teachers like me, but in Germany and people from England who were actually aware and keeping up with a law case my lawyer son was working on in St. Louis, Missouri. You get a chance to see how small the world can actually be.
I had other tourists confide in me they were afraid to try the Metro. We ended up going together and i showed them through the system for 3 station changes and they were then confident enough to do it themselves and were very proud of themselves. It made a great afternoon for all of us .
I stopped in a florist once and the lady wanted to add some greenery and wrap my purchase. We had a nice conversation while she worked.
One of the best parts of traveling solo is that you are not always focused on the person you are traveling with. Meeting other travelers and locals really makes a trip more interesting. Try to be open and let people know you want to enter into a conversation.