There are several established methods for stereo recording. The XY stereo technique is one of the most common due to its simple setup.
To use this method, place two identical microphones with either cardioid or supercardioid polar patterns close together, so their diaphragms form a 90-degree angle with each other.
(The accompanying image is for reference only; please adjust your setup based on your actual recording environment.)
It's crucial to ensure the distance between the two diaphragms is as close as possible without them touching. This arrangement is designed so that the sound reaches both microphones at roughly the same time, which provides accurate stereo imaging. In post-production, you can pan these two audio tracks to the hard left and hard right channels to achieve a full stereo effect.