I'm sorry I didn't read all the posts, so this may be redundant.
This girl is eight years old, right? Eight? She's just a little girl and hell, I'm a teenager and I have a horrid attention span as it is. I was even worse as an eight year old. I rode, I competed, but I was not ever there all the time. I hated warming my horse up at shows. The only thing I liked is showing off in the arena, then I was as good as done. I learned how to really, really engage myself later on. My interest grew the more fun it was for me.
Now, as I have started teaching little kids myself, I have to remember what it was like then. The terms "posture", "applied riding"....They mean nothing to a young girl.
Make it fun....Play some games, challenge to trotting over some poles for some candy or something. Throw some balls into the ring and play catch with her. Get a big horse ball and play soccer. Get on your horse and play tag. Race each other (put gait restrictions on it....) and most importantly, praise praise PRAISE! Remember that kids will rarely remember being praised, but they will almost always remember being scolded. Which means the more you scold, the more resentful and unhappy they will become. Reward what she does right instead of what she does wrong.
Here's a list of games I play with my girls -
Egg and Spoon -
Get a plastic spoon and some eggs. Challenge her to holding the egg while you give a list of commands. (This may be hard if the pony doesn't neck rein....So maybe not)
Tennis Ball Race -
Get a tennis ball/golf ball for her to hold in her hand. (She can hold the small ball AND the reins, it is possible) Set up three poles with a bucket at the end. Have her weave through the poles and drop the ball into the bucket, then turn around and weave back through. Body control!
Streamer Team Race -
This is a team thing...You could get some friends. You tie your stirrups together with cheap dollar store streamers, They break easily and won't get hung up if theres an accident. You each hold an end and have to stay next to each other, you drop one end and you lose the game. Have someone calling a list of commands. More body control this way.
Flag Race -
Like the gymkhana event. Set up some flags in two buckets. Have her pick up one, drop it in the end bucket and pick up that flag and go back and set it in that bucket. Fastest time wins! Teaches a lot of balance with the leaning off for the flag, and control to get that close.
Horse Soccer -
You can order big horse balls. My horses typically will kick the ball around, but you can get brooms to hit them with too...Set up poles or barrels or something at the end to make goals, and let 'er rip! This teaches them a lot about positioning the little pony.
Dollar Bill Race -
This one my girls LOVE. Typically we do this bareback, but it works with a saddle too. Place the dollar bill under her knee. Call out commands and if she can make it through a course (write one out beforehand) then she gets to keep the dollar bill. A lot of times you will see this race in groups of riders and the last one with their dollar bill wins all the dollars. (I've won a lot of money this way ;D) This will teach her to ride with her legs.
These are just some of them...You can always make up your own or google them for more information too. My girls really respond well to these because its fun for them, and secretly they're learning how to ride!
Pssh.I didn't pick up the wrong lead
It's called a counter canter...
...A very advanced maneuver.