There are certain formatting rules and SEO best practices that provide signals to search engines that your content is mostly unique and the curated content is for illustration and reference purposes only.
The content that is borrowed shall be put into quotes. The content within quotes is not indexed or analyzed by search engines and it won’t harm your overall SEO ranking. In case the content is borrowed (copy-pasted) but is put in a simple format, Google and other search engines will detect it and rank lower as the original copy will always be considered the "top one".
The quotes can be optimized further. Citation attributes and tags with back references are good practices of writing quotes the right way. The standard WordPress doesn't provide tools to define those attributes, but if the content is curated with ExpressCurate, that will be done automatically.
Everything else that goes out of quotes is considered your unique content. It shall be not less than 90% of the whole post (accordingly the quotes shall take at most 10% of the post).
In case of copy-blogging special meta tags shall be set to define that the content shall not be indexed. That will make sure your blog doesn’t lose SEO rank.
ExpressCurate automates this process, so you can spend minimal time on mechanical tasks.