Next, we want to pre-heat the fabric. Pre-heating removes wrinkles, shrinks any fabric that may shrink with heat and removes moisture.
Moisture is an enemy to sublimation so make sure you pre-heat long enough to remove any moisture. Even if you think your shirt is wrinkle-free and dry. Don't skip the pre-heat.
With the fabric pre-heated go over it with a lint roller to remove any dust, hair, or other debris that may be on the fabric.