How to get clients - especially the first one

Hi there, we are planning to open a new coworking space in México city in a highly competitive area and would like to ask you a few questions about how to get clients.
What have you done to start with?
What have the key promotional channels been?
How much have you invested in social media campaigns? Have you started it at the beginning, have you linked to events?
Any other tip is more than welcome!
Thanks a lot,