The general etiquette over on V-Flyer is you post your flights in the itinerary forum. Then, if someone is flying that route that day (and not all regulars post their itineraries) they may invite you. Usually, it will be mentioned in their itinerary post if they are extending an invite.

A few people may post a general, ad hoc invitation as a thread, but this is rare.

Actively seeking an invitation is generally frowned upon, especially from people who have made little previous contribution to the forum.