L.G.
Hi Marybeth,
I'm at home now, but taught fifth grade for seven years before being a mom. Memorizing the facts can be so easy for some and such a chore for others. Good for you for trying to help her nail them down. She'll get them, it just might take some time. I'd suggest taking the pressure off and begin by focusing on what she does know.
You could make a list of all the individual tables and check off the ones that she knows by heart (the 1s, then 10s, then 5s). You can find out which ones she knows by using flash cards or making a practice sheet. I've done it with kids that we make flash cards of all of them and then create 3 piles: "mastered", "working on", "to learn". As cards get moved from pile to pile, celebrate in a way that is meaningful for your daughter. Part of the battle might be confidence.
I'd then have her work on 2s, 4s and 8s, though only 3 or 4 facts at once until she knows them and can add them to her "mastered" list. 3s, 6s, and 9s can be grouped as well. Once she knows a fact one way, point out that it counts as 2 (3x4 is also in the 4s as 4x3).
Once you have the 3 or 4 individual facts that you are working on, each night I would have her sit in a quiet place with a sheet of paper with 5 columns. (This should be the same place every night - her brain will associate the place with learning). Have her write the full fact in the first column "3*4=12". She should look at the fact and say it aloud. Cover the fact with another piece of paper or fold the paper to hide the fact. Then she should close her eyes and picture the fact and say it again with her eyes closed. Then she opens her eyes and writes it again in the second column. Repeat this saying, picturing, writing process for all 5 columns for each of the facts. Then have her tell you the facts or you quiz her. This whole process shouldn't take more than 10 or 15 minutes maximum.
The research that I know about has shown that to move something from short term memory to long term you need short bouts of repetition separated by longer periods. So if you were to do this 5 nights a week with a few of the same facts, she should be able to memorize them. This method also taps into different ways of learning which helps too. It worked for my fifth graders so I hope it helps! Good luck!
-L.