If I were you i'd try doing things outside of promo/shoutouts... this should be secondary. You can put a biz email in your bio and maybe once a week or so you can post a textgram pic or something similar reminding people you give shoutouts/promo.
OUTSIDE OF THIS
Look into selling Car related T- Shirts, Items people can use/have in their car, phone cases car related, etc. You will bank way more via ecom to be honest or you could even build a email list and then have a follow up sequence with higher paying cpa offers ( trial offers ) - This is more ideal if your page is cars/luxury. Iv'e even seen people make websites and put viral content related to their niche and than make money with adsense (doesn't have to be google adsense). There's tons of possibilities try testing a few
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