What can you do general?
Nadal makes it harder on himself, by taking the easier path (to him). He has a lot of confidence in his forehand right now, and not much on the backhand, and it's obvious. The player who can tactically take advantage of that will beat him. We saw Spartan Stan do it in best of 5 in Australia and he overpowered Nadal to a point where Nadal strained so much to get to balls, his back went out on him. We saw Almagro do it to him, in best of 3, because he has a lot of power, and Nadal was not good that day and it was only best of 3.
Novak Djokovic is capable of doing it as well if he is healthy. He can hit with power from both wings and take advantage of the space Rafa is leaving open when he runs around the forehand. Nadal has two options. Rely on his backhand more (which is too late now to work on), or his forehand has to be devastating when he runs around it. It has to be a winner or near winner that results in a poor shot by Novak. If Nadal's shot is too weak, landing on the service line or before it, Djokovic will hit the forehand down the line to the empty space, and Rafa just doesn't seem to have that speed that he once had to run everything down.
It's hard to know what each will bring on Sunday. They both are under pressure. Rafa is defending champion again, and is going for #9 at RG and #14 overall to tie him with Pete. Djokovic is trying to break through and win his first.
I think Novak should have a bit more pressure, unless he plays like he has nothing to lose. But I can't see that happening if he goes up a set. Once he thinks he might have a chance to win, the pressure will hit him. The best strategy for him would be to keep it close if he can and get it to a fifth set and hope to wear Nadal down and take advantage of the space Rafa gives away.
Rafa should try to obliterate Novak from the start like he did with Andy Murray. Come out smoking hot, and whip his forehand around and use the clay to his advantage. Novak gets nervous if he feels problems with his footing. Nadal should try to wrong foot him as much as possible, or hit straight to Novak's body. Rafa has to vary his serve like he did with Murray. Murray who usually returns very well against the biggest servers, couldn't handle Nadal's variety of spins and pace change, and generally returned very poorly. If he can do all this and keep it up, I think Rafa should win in straight sets or drop a set at most. I don't think the pressure will get to Rafa unless it goes deep into a 5th set.
That's how I see it sports fans, but I have no crystal ball to know for sure.
Let's see what really happens...

Best of luck and health to both players, and may the best player win!
Respectfully,
masterclass