Close your eyes. Imagine your fingers striking the keyboard. With ease, your ring finger and pinky dance along the keyboard with the same dexterity and security as your other fingers...
A dream? Perhaps, but practice can help to make this a reality.
In addition to playing this exercise as shown, you can also play the same line in both hands or even extend the length of each trill. Try playing each trill for two beats instead of one, and then you can accent each note of the trill if you focus on accenting each beat. Remember to cover each and every key.
Be creative! Music is all about freedom of expression. Don't let anything hold you down!