1. Count while you play
Most people know the melody. This is a good song to practice counting while you play it. If you can count evenly while you play then you are good to move on.
2. Alternate your fingers
Always alternate your fingers. Do not play 2 or 3 notes with the same RH fingers. This will create bad habbits.
3. Check your notes
This is a good some to make sure you know your notes. If is sounds wrong you are playing wrong notes. Double check them.