Ha ha I had one of those. Could move like sh1t off a shovel when she wanted; and could be as nappy as hell planted in the ground at other times. Over time, I mastered it but there was no one trick. I also rode with whip and spurs, I learnt to anticipate her moods and thoughts and actions, I made up the rules as I went along and always won, but sometimes by inventing the solution on the go.
She's probably the alpha mare? You have to be more alpha. By which I don't mean beat her up, nor do I mean a lot of Natural Horsemanship ground work, I just mean that you have to always know in advance what you are planning to achieve, and never let her change your plans. Okay - so you might have to 'go a different route', but make sure she never wins a discussion.
Get up, get going, seize the day. Enjoy the sunshine, the rain, cloudy days, snowstorms, and thunder. Getting on your horse is always worth the effort.