If you plan on grinding/farming combat sectors or areas that require active players, use the Ryuker Device. Teleport to an area you'd like to play in (e.g. Mt. Magnus). At the Ryuker Device, choose Room Transfer and enable "Rooms in Same Sector Only" to On. A list of rooms for that sector will show active players. Find one that's populated or change Default Sorting to Order by Vacancies.