Here’s the best way to level up your specialty like crazy:
– Once you hit your desired level tile (12 is the goal for me), I swap all virus tiles to composite
– Save up massive amounts of composite material (20-30+ million)
– Save up 200-300k diamonds as well
– Reset to green tree (bottom left) and blue tree (1 queue)
– Activate green skill + bonus card if you have it
– Upgrade all your buildings at once within the 30 minutes, you’ll jump up 5-10 specialty points each time you do this
I normally do this twice per season, once in the middle and once at the end of the season.