How close should I be to my microphone?

Four to six inches for dynamic mics, six to twelve inches for condensers. Closer positioning gives warmer tone and better noise rejection. Use a pop filter to prevent plosive sounds at close range.

Do I need acoustic treatment?

For podcasting, basic treatment helps significantly. Even hanging blankets behind you reduces echo. If you use a dynamic mic with close positioning, you can get acceptable results without treatment.

Best Microphones for Podcasting and Streaming