Common sense suggests it's much easier to do an off-field landing at day than at night, curious to know how it's accomplished at night.
Off-field landings at night are inherently more difficult and hazardous than in the day because depending on conditions you may have no way to tell what is down there. Unless you have decently strong moonlight all unlit terrain will be completely black, and you won't be able to tell forest from field. This is why it's critical to protect your night vision, it gives you a chance to see what's below you. If there's a highway down there that may be your best option, but if you're in a sparse area on a dark night you have to pick a spot that's into wind and hope it's not badlands. Even then it's still survivable if you have good technique, keep positive control of the airplane and reduce the airspeed as much as you can before impact, without stalling of course.
Aiming for clusters of lights sounds good at first, but that usually means buildings or parking lots which are not good choices.
The best way to de-risk this is through good flight planning. Choose a flight path that goes over friendly terrain: adding 15 minutes of flying time is worth it if it means you are over fields rather than rough terrain or water. Study the terrain using google earth or a similar tool. If you have a GPS you could even put good off-airport landing sites on your map. Give yourself extra altitude, and keep practicing your forced landing technique.
Chapter 10 of the FAA's Airplane Flying Handbook covers night emergency landings, here are some of the points it suggests (p. 10-9):
- Maintain positive control of the airplane and establish the best glide configuration and airspeed. Turn the airplane towards an airport or away from congested areas.
- If the condition of the nearby terrain is known and is suitable for a forced landing, turn towards an unlighted portion of the area and plan an emergency forced landing to an unlighted portion.
- Consider an emergency landing area close to public access if possible. This may facilitate rescue or help, if needed.
- Complete the before landing checklist, and check the landing lights for operation at altitude and turn ON in sufficient time to illuminate the terrain or obstacles along the flightpath. The landing should be completed in the normal landing attitude at the slowest possible airspeed. If the landing lights are unusable and outside visual references are not available, the airplane should be held in level-landing attitude until the ground is contacted.
Having said all that, every situation is different. Checklists cover the 'mechanical' steps required to make an emergency landing but they can't tell you where to land. The pilot will always have to make that decision and it's a debate that comes up periodically on aviation discussion forums, especially about how close (or not) you should land to lights.