I'd like to learn

[Level 1]

Well, don't do what I had made as a mistake. Look at a good reference of what you want to try and showcase, in your example, a Yoshi Story sprite would be a good beginning, but don't copy it pixel by pixel, try and remake it with different proportions, maybe a bigger head, maybe a longer tail, etc. Play around with the style until you come up with something original, something people can say "Yes that is Yoshi Story style" but doesn't make people think "Well it's obviously just a Yoshi sprite with a bigger tail, cool I guess"