I suggest you turn up and start listening rather than talking. It might be best to go to some of the open evenings and career events that many firms run. I suggest you go to a few that DON’T interest you first as you are almost inevitably going to say the wrong thing, or at best come across as a weaker candidate, and you’d be best using these as training. You’ll soon pick up from the stronger candidates how to network and work the room. After that you can start attending events that are of genuine interest.
I’m not sure there are many firms that deliberately target PhD’s in Economics, but it is a perfectly acceptable qualification for the consulting world.
Your main challenge may well be that larger MC firms have fairly strict entry points – new grad, experienced hire, very experienced hire, manager, etc and you may not fir into any of them (experienced but outside of consultancy/client firm). You might find smaller firms have more latitude in their hiring model (although fewer places to fill).