First, you just learn to count them fluently. After that, you already know all the anwers, which is a huge head start.
I would have her count up and down. So now, just to learn the counting series she also had to do a bunch of addition and subtraction too.
After she could count the series, she could actually guess many of the answers the first time through a set of flashcards. And it only took a couple repetitions to get them all right.
And then, if you forget one, you can landmark off of easier ones, likes 5s and 10s. Since you deeply understand that 6x6 is just one more 6 past 5x6, you go 30+6.
It was fun and cute to see her working out the answers when she didn't know it off the top. And even if you have to count from 0, you're quick at it so it's not a big deal.