Section off your booth. Designating a certain space as a dedicated vocal booth can be as simple as using a folding partition, the kind used for dressing behind. Taking advantage of a corner of the room, one or two such partitions can section off approximately a space 8 feet by 8 feet. A large duvet or comforter hanging from the ceiling could accomplish the same job, but would be harder to move and adjust.
Apply insulation. A home vocal booth will likely not be completely soundproof, but it can still create a good space for recording voices. Acoustic foam, or egg crate foam, is an inexpensive way to dampen unwanted echoes and reverberation in a home studio vocal booth. You can also use blankets or carpet. Be sure to nail or staple the insulation to the wall and partitions to ensure a secure attachment. The surface behind the singer is the most crucial surface to cover with sound insulation.
Position the mike stand. A microphone stand is necessary for each microphone in the booth. The stand should be fixed in place with tape to avoid incidental movement. As mentioned, the stand should be positioned so the vocalist's back is to an insulated surface.
Clamp on add-ons. Two essential add-ons can be clamped directly to a microphone stand to create professional-sounding vocals. A vocal screen, which is fairly inexpensive, should be clamped to each mike stand and positioned in front of the mike to prevent recording unwanted popping. A reflection filter, which is like a mini composite-material wall, is clamped to the stand and positioned behind the microphone. This piece of equipment sells for about $150 and significantly reduces unwanted room ambience.