@chrisaakins I'm not sure if this is accurate at all but what I've heard about Instagram is:
the quicker you get interactions the more people its shown to, if you get a comment and respond straight away your post is more likely to be visible to more people, and it can snowball from there
If you use the same hashtags all the time you will not be shown to as much people as you are considered spam
If after posting you go back and edit your text this restricts the amount of people its shown to
Time of the day you post
Apparently posting stories regularly too helps boost your exposure when you do a grid post
I've also heard using 3rd party posting apps to automatically post are not good
All of the above might be rubbish
And it definitley comes down to what it actually is your are posting and a bit of luck too.
Try not equate the amount of likes to success, the amount of likes you get can be quite random and it can be detrimental to an artist to link the 2.
My advice when you get loads of likes enjoy it, it means your audience enjoys your work. If you post something the following day and it gets very little this could be completely random and have nothing to do with your work.