I had a couple of students in the past who tended to miss notes here and there during music reading. This isn’t an unusual situation since there’s so much going on when someone is reading music. A few things can improve the situation if you’re one of those players who seems to overlook music notes:

• Count out loud while you play. It’s hard to drop beats in a measure if you’re counting “1, 2, 3, 4.” And before you ever play the piece, consider tapping and counting out loud. Sometimes I’ve assigned just the tapping and counting for a week before the student starts learning the notes.
• Have someone play the piano with you – not the duet part, but your part. That is, you’re both playing the same notes at the same time. Assuming you have another friend or family member who can read and play well, you can have the person sit next to you, and you both do the same part together. Sometimes I sit with the student and play exactly the same thing but two octaves higher/lower so the student gets to hear the music while he’s playing.
• Play along with a recording of the piece when you practice at home. Imitation will help reinforce the learning experience.
• Alternate measures or phrases. Here’s another exercise that needs a piano buddy. You play one measure, he plays one. It forces you to keep track of the musical notes. You can also do this with just tapping the rhythm.
• Plays left hand or right hand. This exercise is similar to the one above. Your piano buddy plays with one hand, and you play with the other.

Let me know if these suggestions help.