Building Document Management System with multiple types of files and types

In my work we are building EDRMS (Electronic Document and Records Management System) based on SharePoint. In simple terms all employees will use EDRMS to store and collaborate on documents. At some point one library can contain between 150-200 documents.

What I'm interested is how to help users to retrieve information before going to search. Before few ideas, which is the most effective and if there are others I omitted.

2. Metadata Filtering
3. Color Coding of document from the same type
4. Icons for documents from the same type
5. Grouping of documents from the same type