When you see a post you want to read later, share it only with your “Read later” circle. Later you can open that circle to read, delete or share those posts.
Whenever you get an idea for a post, but no time to write it, draft a rough version and share it with the “Drafts” circle. You can edit the draft by using “Edit this post” from the drop down option menu at the top right corner of the post. When the post is complete, copy it into a new post that you can then share to your circles, then delete the draft post. At the moment there doesn’t seem to be a way to change which circles the post is shared with after you post something.
You can easily extend these ideas to collaborative sharing and editing.
Hat tip to David Yonge-Mallo at Google for this tip.