I spent 6 years looking after events for IoD Berkshire and spent a lot of time asking members what events worked for them. The common answer was events that draw repeat attendees. A good example are certain types of breakfast clubs. The benefit comes from being able to build a relationship over time and stay in peoples minds due to repeat contact. There is no one specific format such as informal networking, speakers or topics that always works the best. However, the event has to provide the opportunity for attendees to easily get engaged in conversations with several different people. Of course the event has to be interesting to get people to attend in the first place.
My advice is to find an event that repeats several times a year that you feel comfortable at and keep going to it. Going to the odd event and hoping to get lucky finding a lead or good contact is increasingly unlikely. It’s a bit like belonging to a club. Have a goal of following up one person that you meet at each event you attend and getting them to join you for a coffee.
What about weekly meetings?
Personally I think that weekly meetings only work for certain types of businesses. Mostly trades and business to consumer companies.