What kinds of events are there?
There are only so many kinds of social events that work: conversation event, study group, translation group. A conversation event is where people only speak their second langague. In a study group, everyone works from a textbook. A translation group takes a text and attempts translate it, usually from the second language to their own.
Something I won’t talk about is tutoring and classroom teaching because that is for real teachers who are teaching the language as a full time career. Likewise, cultural events don’t necessarily involve doing anything in or with a foreign language, although going to a foreign film is close.
Tips for a good conversation event
Be strict about speaking the second language.
Fight the urge to be polite and constantly switch to English.
Bring a dictionary, but try to use it only in extreme emergencies.
Absolute beginners will benefit, but will often feel awkward and uncomfortable.
Intermediate speakers will benefit the most.
Locations that are quite are best for communication, but people usually like to go to noisy bars and cafes if they go anywhere at all.
Having just over 50% of the poeople at the table who speak only English will often cause the entire table to switch to English.
The event works well for as many people as you can get to attend, unless the hosting restaruant gets mad at you.
Fluent speakers generally are happy to participate because a table full of people talking is entertaining.
You can organize a conversation event without yourself being fluent, but you run the risk of a failed event if no one shows up who is half fluent!