Part of why most of you dudes never get anywhere is because you just text girls and probably overthink the shit out of it. Your chances of flakiness I found greatly decrease when you call up someone to make plans, why? Rapport. You call, ask her how you doing and what fun shit she's up to. Then be like "so I wanted to go with you to A at X time blabla", give her options as well if she's busy.
Even if she doesn't pick up it puts the ball in her court because she has to answer you eventually. Texting isn't that bad I'd text if the phone call don't work, just don't only text. If she don't answer she's not worth your time. This might be harder for younger folks (feels weird saying that at 25 but most kids are awkward af and don't know what a phone call is), but it's great to solidify a plan since she knows you better and is more invested that a robotic and unemotional text.
I was raised in Europe for a part of my life so it might help but you can do to.

Example: Girl HB9 I meet I actually FaceTime she doesn't pick up until the 3rd laughing asking why I'm video calling I tell her I wanted to see that pretty face etc after some laughs I set a plan and everything ends in the bedroom.

Example2: This HB7 met on Tinder and lost her number somehow but then found her Snapchat.
Right off the bat I can tell her she likes playing hard to get so after about 2 weeks of infrequent snaps I videocall( had no idea snap chat had that) and she never picks up. I'm like fuck this hoe that's it imma bounce. 30 minutes later snapchats me apologizing but says "ok I'm free Tuesday let's do dinner and drinks ". Knowing what that means it pissed me off and forget about it.
She was so invested that in less than an hours asks me what works for you. That’s it from there, everything ends in the bedroom.