How to Loosen The Precision to Do The Combos Successfully
Clicking and dragging the mouse across the 3X3 combat panel helps considerably with this. It doesn’t seem to require as much precision on the panel as it does on the main screen. I would be sure to have it up when performing combos.
Also, make sure to turn the graphics settings down. Having them at high settings can cause frustrating mouse cursor lag, especially on lower end systems like mine, which makes it more difficult to smoothly move the mouse and to accurately line up your weapon swings. There are other similar posts about this problem as well, that you can find.
Another tip I would pass on, is that once the line is drawn on the combat panel, you can keep holding the mouse key down afterwards to save the attack until you want to use it. I’ve observed that it works similar in function to charge attacks, which are in many types of games, except instead of only briefly holding a button down and releasing it when you are ready to unleash it, you are also tracing the required path beforehand. I hope this of some benefit to you.