Use photos with a clean subject
A good photo has one subject, enough light, and a pose or face that can be exaggerated into a sticker. Background complexity matters less if the final sticker has a clean cutout.
Choose the right pack theme
A selfie can become a reaction pack, a pet photo can become a cute pack, and a mascot image can become a branded support or community pack.
Check the sticker edge
Sticker quality depends heavily on the border and transparent background. Clean edges make the sticker look intentional in chat apps.