While there's a lot of information about copywriting on this site, never lose the idea that all copywriting does is multiply or duplicate your best sales message or sales process.
That means that whatever medium you're using, it's about doing whatever it takes to make the sale while adding tremendous value to your client's life by offering what he wants.
When you're writing the scripts for your videos, you follow the same process as in a sales letter. In fact, it's been proven over and over that the best converting simple sales videos are nothing more than the text of a great sales letter spoken and shown. Ryan Deiss is awesome at that.
What matters is the sales process that you're taking your prospect on. Point A is getting the attention of your most qualified prospects. Point B is the conversion of the prospect into a customer. Everything after Point B is about making larger and more frequent sales.
So whatever you're using to generate leads - online, offline, doesn't matter - what is your process for converting that person into a customer. Remember the small sale first if that 's what it takes. [Small sale is relative to your market, by the way.]
Then, once you have a customer, he/she is much more willing to buy from you again because he/she has already purchased something from you. As long as that first product or service gives them what they are looking for, or more than they're looking for, but still focused on the exact result promised, your future sales with that customer are nearly assured.
Just keep in mind when you're studying the information on this site, everything you write and do is part of a sales process, a process designed to get the qualified prospect on your list as a prospect, then on your customer list, then on your repeat customer list, premium customer list, repeat premium customer list, ultra-premium customer list, then repeat ultra-premium list.
It's about the journey of their personal experiences from the moment they first put attention on your company on through the process toward repeat ultra-premium client or customer. Got it? Good. 
Stay Great, 'Migo.