What to set my wordpress permissions as?

I’ve had an issue creating posts/editing my wordpress site, it won’t let me.

I think it’s a permissions issue, I’m now checking my site permissions but have no idea what to change and what to change the permissions to?

It seems all the wp_content files are 664 (which seems right?) apart from one – public_html/wp-content/uploads/slideshow-gallery/cache which is 777 (could this be the one causing the problem??)

If not which permissions should I be looking at changing/looking for problems with?

Thanks!