At the end of the day, SharePoint Online's main job is to make it easier for your Office 365 users to find things; it's a curated version of all your Microsoft Office 365 documents and data. Thus, one of the main complaints that SharePoint administrators have to deal with is, "I can't find what I'm looking for."
Fortunately, SharePoint Online has a number of tools to make online search better, and SharePoint admins' lives easier.
Hack 1: Create a KQL "cheat sheet" for your SharePoint users
SharePoint online supports a number of search options, but the most powerful is the Keyword Query Language (KQL), a set of search operators that make it easier to find exactly what you're looking for right from the search box. KQL may be overkill for many users, and can confuse SharePoint team members that haven't dealt with search operators or a query language before. However, a stripped down KQL "cheat sheet" that explains a few of the key operators -- using quotes forces a search for an exact phrase, using the plus or minus sign can make a phrase required or forbidden from the results -- could do wonders for your users' search habits.
For example, you'll never receive a bigger thank you than when you tell the finance department that filetype:xlsx will limit search results to Excel spreadsheets.
Put together a quick cheat sheet, post it in a common area (or in a persistent sidebar) and save yourself an incalculable number of help requests.
Hack 2: Use managed metadata to enhance SharePoint file browsing
Most Windows and/or Microsoft SharePoint users are familiar with the standard metadata around stored documents: the filename, the filetype, the last modified date, the file size, and so on. However, SharePoint gives its newer versions (and Office 365) the ability to create and manage new metadata types to distinguish between different file categories via the managed metadata feature.
With managed metadata, a school could distinguish between Curricula, Syllabi, Tests, and Assignments, or a sales organization could distinguish between Sales Analyses and Customer Case Studies. Building a nice set of additional taxonomies for your documents can make SharePoint browsing much easier, just make sure you keep the entire company in the know.
Hack 3: Use document sets to impart SharePoint metadata in bulk
SharePoint allows you to "enforce" good metadata habits with document sets. Think of document sets as folders with extra features. A SharePoint document set can control which types of documents are allowed or included in the set, and what sort of metadata those documents will automatically inherit if they are added to that set.
Document sets can also include a welcome page that describes the set, and the rules that govern it. For example, a document set for the Engineering 101 Fall 2017 Assignments could require that only Microsoft Word or Visio files are allowed in the set, and that every item added to the set is given the Assignment metadata attribute.
With document sets, you can make sure that SharePoint files are properly classified when they are organized, which makes future browsing and searching much easier.
Follow these three tips and watch your Office 365 SharePoint search complaints decline. And if your users still can't find the SharePoint files they're looking for, they probably deleted them. If that’s the case, don't worry, you can still find those O365 files, too.