Creator Academy has tons of tips for you. Check out the course on creating great content: https://yt.be/help/eovr . You can also browse the catalog for more: https://yt.be/help/6Br
We recommend you make changes (deleting or editing) your content and be sure to add your own unique, creative value to be eligible for YPP. After making these changes, you can reapply 30 days from the date you received your email. That will send your channel for a new review.