Connections seems to be purposely tricky. 
They often have one or two categories where 5 of the words could potentially fit.  
You have to find the one that has multiple meanings and could fit in another category. 
Also, if you don't know a reference, it's totally trial and error.  
For example, today I knew humble, match, tinder were all dating apps.  I figured grinder could be either a dating app (although it's spelled grindr) or a sandwich.  However, I never heard of hinge, so that had to be a guess.  
Also, I knew Lost Boys and Twilight, but never heard of Blade or Near Dark.  
The purple category can often be maddeningly abstruse.