I'm very new to Instagram myself but looking at your Instagram, perhaps you can post more of your finished drawings instead of your sketches. Maybe you can vary/not use the hashtags on every post. Like one post you use hashtag art and the next post you don't use that hashtag, rinse and repeat if you don't know any other hashtags.
And maybe you could try posting 3 or two times a week. But don't post it all in a row, leave some day or days where you don't post anything. Post slowly over time and not all at once.
Anyways, I gave all your posts likes so hope that helps 
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