Hey there! I'm sort of new to being a Pinterest creator, but my account has been slowly growing since March. A big help to me was adding in popular alt texts and detailing the description on all my pins so it reaches the right audiences. If you don't know what to tag, go to the normal search bar and search the basics of what your photo is. For example, if you're posting a picture of a sunset, search up 'sunset' and the drop bar will fill your screen with everything Pinterest users are searching for in relation to sunsets. Use these searches in your alt text and descriptions and it will help get your pin on more people's screens.
Hope this helps!