Not knowing anyone is gonna be a bit tricky so on to part 2, have you got money? If you have some money to spare you can hire a venue for a night.
I would suggest getting out there and meeting people. I know a lot of people say that but it's pretty much the 1 thing that matters the most, building good relationships. I met a guy one night when I was running my own night. We had a chat and a few weeks later we had a tune signed and it did ok. He expanded his network base and started playing in venues while he was here so it's a big help