How to select which conferences I should attend?
There are many different types of conferences and many different reasons to go to a particular conference.  The most relevant that I would say for your situation are:


Flagship conferences that everybody in a field goes to because that's where everybody goes, and where research presented will get the greatest audience.
Niche conferences and workshops that serve some particular smaller interest group.  They are less prestigious, but are where the communities they serve have a lot of key interactions and get a lot of actual intellectual work done.
Crap conferences that would like to fool you into believing that they are one of the first two.


Some good tactics for judging the quality of a conference:


Where do the people whose work you respect (particularly your advisor) publish and attend?
Where are the organizers and program committee members from?  Are many of them from high-profile research institutions?
Google Scholar metrics


Given your early stage and breadth of interests, I would recommend going to one of the broad flagship conferences, where you can hear about lots of things from lots of different types of researchers and organizations.  Those conferences often have a lot of industry attendance as well.  I don't know your specific field too well, but even from outside I know that USENIX is a large conference with a strong reputation.  Still, use the heuristics I suggest and see if it's really the one you want...