You can perform a simple at-home test by washing your face with a gentle cleanser, leaving it bare for an hour, and then observing its condition. If it appears shiny, you have oily skin; if it feels tight or flaky, you have dry skin; if the T-zone is oily but cheeks are normal or dry, you have combination skin; if it shows redness or irritation, you have sensitive skin; if it feels balanced, you have normal skin.