Do you know which high 8 to shoot?
The high 8 on your opponent’s side is the most difficult to roll on.

Do you know how to score on a high 8?
If your opponent puts one on his side, you move over to the 3 position and shoot right at it. You will roll right over to your 8; try it.
If it is on your side of the board you have to shoot firm to hard just off center to make it roll, it will, try it.
I used to practice scoring on high 8s with another player, you should do that and I should practice it myself.