Canned opener or not, i reckon there has to be an element of improv and vibing in there or it will come off a bit forced, which is the last thing you want. Feed off their reactions to your opener a bit, theyll respond to a decent opener and if you put your mind to it there's an interesting response to pretty much anything they say that can keep a conversation going (except if they give 1 word answers maybe). It's almost like doing a mind map in a conversation, everything connects to something you can bring up.
Im not exactly an expert but thats the way i keep conversations moving in general interactions as well as pickups and it seems to work for me.
It always comes off well as long as you keep cool and just try and have fun above all else, its the natural way conversations work really. Canned responses are nice as a safety net but like aofelix said, theres no substitute for enthusiasm