The only two first lines I ever try are "hey _____
(emoji smiley, no text bullshit) youre really cute" or "whats a beautiful girl like you doing on an app like this?". I also don't keep trying to speak forever, but it usually doesn't take that long to get numbers either. My main tactic on the hunt is bringing up the subject of Netflix. At some point, when you're learning about her boring shit that she likes to do, she will possibly mention watching shows or movies on netflix. If she doesn't, talk about how you do, then ask if she does. An example of how it should look:
you: what do you like to do? do you watch any shows on netflix or anything?
her: yeah I love orange is the new black, finished breaking bad... (etc.)
you: haha yeah breaking bad is awesome! right now im watching _____ (whatever show you might watch)
her: she might say she watches/likes that show, maybe she doesn't. either way it doesn't matter at this point.
you: depending on what she says, respond accordingly, then use this line: "we should chill some time and watch something! whats your number?"
If she's actually interested, or isn't just on there to talk to guys (some girls are), it shouldn't be too hard to get at least a few numbers. Even so, if she's in your apartment and you're chilling on your bed "watching" something for 5 minutes before you try to move in to kiss her, that
does not mean you're guaranteed to get laid. I've had multiple girls be cool with making out and letting me suck their tits, even play with my dick, but still didn't want to fuck, and that does suck. Which is why I also never drive anywhere to meet them anymore, they always come over to my place. I've had a girl come over, start making out, try to make some moves on her and she says "I don't want to have sex, I'm sorry. My boyfriend just broke up with me." When she got up to leave, I didn't stop her. She literally drove about 30 miles to get to my place and left within about 10 minutes. Glad I didn't waste my time or gas.