Using document library for project management.

Hi,

I'm looking for some advice on how to manage document libraries when it come to project management.  We have SharePoint 2013 and have recently started setting it up for managing our projects. The first part is our project tender process. This is when we bid for projects.  I have created a single document library to hold all these documents.  Each tender will be created in it's own document set within the document library.  
I have applied several categories to the tender list, such as the status of the tender, (i.e. tendering, submitted, won, lost, etc) and the type of tender.  This gives me around 10 different views.
Now, where the issue lies is the number of files that are now in the document library.  It has just gone over the 5000 item threshold limit. I know that I can go into the settings in the administration panel and increase this threshold.
But, rather than just increasing this threshold, I would like to manage it differently.

It is not affecting our system yet, but I would like to jump on the current issue before it becomes a bigger problem (if it is one) :)