eg. "THIS ONE THING has been an absolute game changer for my [x, y, z]"
You can always hook someone in by appealing to their curiosities or ego.
eg. "I know first-hand how exhausting it can be to struggle with [x, y, z] your whole life" + [personal story]
Once you have their attention, the best way to keep it is to relate to your reader with a personal story. Once they feel like you really know what they're going through, you'll become that much more memorable and trustworthy.
eg. "Throughout this video, I explain exactly how I overcame this issue, and I hope it helps you as much as it did me."
In this part, you need to provide a clear solution to the problem you just spoke about, to provide value AND maintain your reader's interest. TIP: Showing them how is always going to be more powerful than explaining via text.
4. CTA (Call-to-Action)
eg. "If you have any questions about my experience with x,y,z, comment below."
Never be Afraid to ask your audience for what you want. A call to action is a clear way to do that. Want comments? Ask for them. Want them to DM you? Let them know DMs are open!
Some more tips
Instagram has started ranking posts based on keywords used in captions! This is similar to SEO (where websites rank based on keywords) but is a function inside the social media space!
So make sure to use words that are relevant to your industry and ideal customer in your captions. This will ensure your post gets shown to your ideal customers when they search for a business like yours.