Drips on the floor: Remove latex with a water-dampened rag; use mineral spirits for oil paints. Scrape dried blobs with a utility knife.
Bubbles on drywall: Pop and scrape off with a putty knife. Then sand the area with 330-grit paper, tack it with a damp cloth, and use a foam pad for touch-ups.
Lap lines on plaster or drywall: Repaint the area, applying light pressure on a roller that has soaked up only a quarter of a full load of paint.