Hard to recommend upgrades to a MacBook Pro that is that outdated. It can only run up to El Capitan (10.11.6), which apparently, isn't receiving updates anymore. That's 3 OS's out of date.
If it was relevant, I would suggest an SSD upgrade, and max out the RAM. But with such an outdated machine, it's hard to justify spending money on such a device. Honestly, you're better off selling it and putting the cash into a newer laptop. Even with my late 2011 13" MBP I'm at a crossroads... sell it now while it's still semi-supported (it can run up to High Sierra), or keep it for another year or two until Apple leaves it out in the cold.