How do I speed up the processes of sprite making without quality loss

[A normal guy]

I made this sprite rotation is two days and im proud of it but it takes to long and I have school aswell so how do I speed up the processes of sprite making without quality loss?

 

[DylanDude]

Practice. As you make more sprites, they'll naturally become faster to make... mostly. I should say that two days for a full rotation is already pretty fast, though.