Prioritizing a snug fit is all the more important. So, to double mask, wear your first mask, such as a surgical mask. Now, knot in the loops of the mask where they attach to the edges. Tuck in and flatten any extra fabric, close to the mask. Once done, layer up with an additional mask like a cloth mask.
The CDC also recommends that while wearing a double mask, the outer cloth mask should push the edges of the surgical mask against your face.
It’s also important that you ensure that using two masks doesn’t compromise your comfort. While a lot of people hesitate wearing masks or wear poor-quality ones which do not let them breathe well, make sure you double mask and get comfortable with the fit. Wear it and get habitual around the fit for a while to assess fit, and check if it allows you to talk well.
Remember, a good mask (or double mask) should not let the air escape and instead, masks should press in with the airflow.