First of: depends on what you mean 'organizng a meet after a week'. You mean you get the digits and you wait a week before you text/call? 'Cause in my experience, they usually forget who you are after a week
Leaving a week before the meetup - this is entirely up to you. So long as you don't go for the extreme, like call her the next day and try to meet up that evening, you'll be fine. But leave her some time before the actual date - I usually wait less than a week (say I meet her on saturday, I'll aim for Wednesday-Friday, depending on her schedule). I know there's this whole idea of 'always be busy', but some guys take it too far and therefore miss a lot of dates, just because they're trying to project an image.
It's always good to keep in touch, just sending random texts and calling. So long as it doesn't feel like you chasing her, it's OK. If you send 3 texts and there's still no response, that means she wasn't really that into you.
Sending the odd flirty text then and again is always a good idea. It keeps her thinking about you, and that is a big attraction builder. Her investment (in this case, investing time into thinking about you) amps up the attraction. If a girl doesn't think about you, you'll quickly become 'the last guy', as 'the next guy' keeps her mind occupied.