Answer:
Practice makes perfect!
Step-by-step explanation:
Scales can be hard but the best way to memorize and perfect them is just practice. If you are practicing for an audition I recommend every time you mess up starting over. This helps you train yourself to not keep making the same mistakes. Additionally, if there are notes that are hard I would work on just those notes. So lets say D was hard just practice CDE and then slowly add to it so CDEF, CDEFG, CDEFGA, CDEFGAB, CDEFGABC. And then you'll get the hang of the going from note to note.