You'll minimize noise by using both the mic's pattern, sensitivity and acoustic treatment.
So, probably face the window if that's a more constant source of noise. I'd put blocking drapes over it, but unless you can really close it up, or it's facing a quiet, interior courtyard, perhaps, that's where a lot of noise is coming from. If you've got computer equipment that's also a noise generator, put it under the window, is also an idea.
Then, plan to work close to the mic, and, yes, a reflection filter is not a waste, but keep in mind that most of the sound entering the mic is coming from your mouth, and then whatever is also coming from behind you. So, treat that wall behind you, and if you're lucky, that will be along the long dimension of the wall, so reflections from behind you will be diminished by distance.
I would treat the parallel walls, i.e., those where you'll be singing perpindicular to, to reduce standing waves setting up in the area where the mic is stationed.
And treat the corners well with bass traps because that's where lower frequencies can build up. Even though you're doing vocals, there will be noise and some content in those frequencies you don't want setting up house while you're recording.
Once you've got your initial spot and treatment in place, do some tests and experiment moving the mic around. You might need to treat overhead or move your position as you test.