Simple and at the same time really cool openers if you want to increese your response rate:
1st
me:"hey wish me luck I have an exam tomorrow"
if hb is interested she'll most probably ask you a question about it.
2nd
me:"Locked myself out of my room. Can I stay at yours?"
It is a powerful text because even though you're joking the sexual inneodo is there. No matter what hb is texting you back hold your frame that you don't have a place to stay for tonight and you might even get lucky
Note: These are field tested and proven to work. Don't blame it on the texts if you've already killed it before !!!