Get some blank carts (in addition to the prefilled ones that come with it, and I recommend you NOT think of that as how they "should" taste), and plenty of juice. Get it in small bottles, in several different flavors... and better to err on the strong side than the weak. If you can add in some plain PG or VG with your order, then you can thin out the juice if it's too overpowering.
Smaller bottles might be a tad more expensive, but they're better than being stuck with 20+ ml of something you hate. Plus, you'll get an idea of how good vaping can taste... DON'T get all tobacco flavors, please! Get at least half in other ones...
I'd also suggest at least 30ml total juice with your first order... that should give you enough to last you until you can find ones you like, order them, and get them in the mail before you totally run out

There's nothing worse than deciding you're not ever going back to analogs, and then running out of juice!!