Who says there is a trick in getting your post recommended on the Instagram explore page. To be honest, there is no trick, it is just to based on luck and the money you have to push your post. If you didn't pay for ads, you need to prepare to wait till anytime it picks your post, but using trending audio even if it didn't match your video content helps too. What Instagram needs is just engagement. Meaning, you need to start posting when everyone is online because that's when they scroll the most and there's likelihood.that your post be viewed.