Many pianists can read pitches slowly but fall apart rhythmically. Look for exercises that isolate rhythm. A great file will include "rhythm-only" lines before the pitched exercise.
Memorize the "Landmark Notes" across the grand staff: Bass C (second space from bottom), Middle C, and Treble C (third space from top). Practice identifying how far other notes are from these landmarks (e.g., "that note is a third above Middle C"). Blind Playing (Tactile Awareness)