High humidity may temporarily swell wooden drawers, causing them to stick. If sticking persists in drier weather, lightly sand and then lubricate wooden runners with wax or soap, or clean metal slides and apply a small amount of grease. If you see any loose joints in the drawer, reglue them.
To fix a split drawer bottom, glue a canvas strip along the underside of the split and the bottom edges of the drawer sides. Use white glue.
Flush-front drawers sometimes get pushed too far into the cabinet. To prevent this, glue or tack small blocks of wood to the rear of the drawer runners to serve as stops.
If a drawer tilts when you pull it out, add kickers to hold it horizontal.