Make the "Title" a required field when attaching a memory
Make the "Title" a required field when attaching a memory and maybe add an hidden example of what might be a suitable title on a memory so people know how to put an appropriate title on the memory they are uploading. More often than not people are uploading without any title on the memory or one that is so generic that it doesn't really describe what the memory is.
Another idea is to make the "Title" field open so another family member can add the missing title if the original submitter leaves it off. Often when an email is sent asking the person who uploaded the memory to add a "Title" they just ignore the request.