A) Always seed a date down the road. Do NOT leave it hanging with something non-specific.
B) Don't get her contact info right away if you can help it. Let it simmer after mentioning doing something.
C) When you close, do NOT ask for the number. Say some variation of "What's a good way of keeping in touch?" If she gives you her number, then great. If she gives you an email then take that as a sign you have more work to do. If she gives you her Facebook info then it's actually a good thing. Treat it like text game and work your way up from there.
D) When setting up the date down the road (which you seeded earlier in the interaction), ask when she's free in the next couple weeks. This will filter out the ones who will say they're too busy since women rarely know what they're doing every night for the next 2 weeks straight. If she really wants to go out with you she'll give up at least one night (or more) that she's available.
Around 10am the morning of the day you're supposed to meet send her the following:
"Hey, I've got a quick errand to run after work and will be 5-10 minutes late tonight. Is that cool?"If she's sketchy and going to flake then she'll likely latch onto this to excuse herself from the date. This will significantly cut down on time you waste getting stood up.
h/t Adam Lyons