How do I let people know about my new subreddit Photography group and aim it at existing Photo communities on here?

Hi!

I just started a new subreddit yesterday for Photography Teachers and I'm wondering what is the best way to let people know about it but to specifically target those who actually follow photography groups? I will preface this by saying I'm rather inexperienced with reddit.

I don't want to post on the bigger photography groups here without consent because I'm afraid it's bad etiquette to promote your group on their accounts unless you've been given the ok.

I've messaged a couple of them to ask permission but haven't' heard back.

Any advice would help-thank you!