Dust on the front element is rarely urgent; dust on the sensor shows at small apertures. Diagnose with a plain sky shot at f/16 before you open anything.
Use a blower first, never canned air that can spit liquid. If spots remain, use a proper sensor swab matched to your sensor size—or pay a shop.
For glass, a clean microfiber and proper lens fluid beat shirt tails. Circular motions from center outward reduce streaks.
Work in a low-dust room and cap lenses when swapping. Prevention beats heroic cleaning sessions.
