Let's talk about the room. I'm recording in a bedroom about 15L x 10W x 8H. Plaster walls and ceiling. Pine wood floor with an area rug. There's no bed. I built a studio desk and I've got an Ikea shelf/cabinet system to store stuff.
There are no sound absorption panels on the walls. I will do this at some point but for now I do have a number of 1ft x 2ft x 2inch thick panels of 703 fiberglass. I created a thin frame using aluminum L wrapped around one side and riveted where the ends come together. Then wrapped both with some burlap cloth. I position these items on nearby walls or on the floor where I think they're needed. I think I'll build larger versions for better functionality but I especially like being able to move these where needed.
The room has reverb and standing waves as any room would. Microphones pick up some nasty high frequency ringing in certain areas. I used to just set up a mic and start recording. I noticed these high frequencies in the past and just thought it was the guitar or the mic and I'd just try to EQ the problem away. That rarely worked and the recordings suffered. As I read more about acoustics I tried moving to different spots in the room and there was improvement.
The room has a closet with sliding doors. The sliders are old and the doors come off easily. Rather than repair it I use this as a backdrop for a vocal booth.
I set up my vocal mic so that my back is facing the open closet. The closet is full of shirts and pants so there lots of absorption. I've tried the opposite, where I'm singing into the closet. I'm not sure this was the best method. My thinking right now is I sing directly into the mic, the sound moves away, bounces around but much will get absorbed by the clothes before returning to the front of the mic.
Behind the mic. I place a blanket draped over a boom stand formed into a T. On the side wall I prop some panels. Sometimes I place panels on the floor. Sometimes pull the area rug back to expose the floor.
I place my body so I'm singing on a angle in the room. Like making a bank shot in pool. If I setup exactly square to the room more sound will bounce straight back but if it's on an angle its gonna take more time to bounce around and disperse. I also listen closely for some boxiness that may come from being to close to the closet or side wall.
Overall this works well. The vocals are tight with little reverb but if I sing some loud parts I can pick up some of the room.