.... I'm the same, I'm retired and not interested in selling my work. Instagram really is great for inspiration and ideas (and also encouragement for your own efforts). It will take a little time to build up and so the best tip I can give you is to Follow all the people whose work you like or admire. However, do not ask people to Follow you, let it happen naturally and because they want to.
.... Sorry but I don't see enough on your page which inspires me to want to Follow you. That doesn't mean your images on Instagram are crap, it just means that not enough of them inspire me personally.
Only just got around to setting up Instagram, not sure to just add new content or move any of my older stuff over to it so a little sparse at the min. Main focus will be portrait type stuff but will be other various bits when and as, nothing commercial for me just sharing and looking for ongoing inspiration and feedback.