Would these be good conversational openers?

I'm not that good at opening with girls and I just wanted to know if these would be good converrsational openers. If they suck, don't be afraid to say so, maybe give me a few good conversational openers.

"Hey I saw you after school yesterday."

"What did you over the weekend?"

"So, what do you think of the weather?/Nice weather today, huh?"

"What are you studying?"

"What did you do yesterday?"