Mass Effect: How to grind singularity?
Solution 1:
Based on the guide at Xbox360Achievements.org, it sounds like it does have to target something (it suggests targeting one of the rapid transport stations on the Citadel).
If you only want to play a Vanguard in Mass Effect 1 in order to play that class in Mass Effect 2, there is no need to play through Mass Effect 1 again, though. At the beginning of Mass Effect 2, after importing your character, you are given the option to change your class (don't worry, it makes sense in the context of the story). So you could always import your Engineer into Mass Effect 2, and then select Vanguard as your class without having to play through the first game again.
Solution 2:
Unfortunately, skills don't carry over between the two games, and bonus talents themselves are handled a little bit differently. Until the latest DLC for mass effect 2, it wasn't even possible to get singularity as a bonus talent.
If the only reason you want to earn the singularity achievement is to have the ability in mass effect 2, give up now -- it's simply not possible.
If you want the achievement for the gamerscore, or just like the option of having singularity available as a bonus talent, you will have to target something. As others have mentioned, the transit hubs make good targets. Another option is the two turrets when you're fighting Fist. The fight with Fist doesn't end until both he and his turrets are destroyed, so you can continually duck out of cover, use singularity on the turrets, and then wait out the cooldown to do it again. (This is the same strategy suggested to farm the AI hacking achievement).
Though squadmate uses do not count, usage counts carry over between playthroughs, and even between characters on a single profile.
Solution 3:
I was just looking over what was said here and I had to post cause I see some incorrect information.
Anytime biotic abilities can be used, it goes towards the achievement, and bonus the talent. I have 3 accounts I play Mass effect on so I have done this over 3 times. You don't have to target anything with biotics, just activate them. Loading a game is a fast way to do it at a low level, but if you play the game and fully upgrade the ability it will recharged faster than a loaded game. Have fun with it, thats what I did.
Also, Singularity is not a bonus talent in ME2, you get stasis from Liara. If you want Singularity you have to be a Adept now. Certain moves are one class only now, so the Vanguard's Charge move is vanguard only.
Solution 4:
Singularity used by companions do not count towards the achievement such as having Liara T'Soni in your party at all times and have her spam singularity as much as possible.
Achievements counting only works when targeting targets. Targets can be enemies, elevators, etc.
However in Mass Effect 2, companions do count towards achievements