DownandOutInandAbout Choose a place close to a metro station and based on where your work/study is. While you can get anywhere in Delhi with the metro, ideally choose a residence which does not require you to connect in any station.
There is a cultural angle. If you are Southie, Munirka/Vasant Kunj areas may be better since "our" food items etc are easily available here. I stayed in Dwarka for 2 years but I wanted a place outside the hustle and bustle of delhi while still being able to get into town to meet friends when reqd.
As for the trans thing, yes it might be difficult to get accommodation. My former landlord turned down another trans friend of mine. ? But if your girlfriend is "passable", it should not be an issue - just don't mention it. I am just being practical.