Hi !
When I try to hit my PB in static (as well as in dynamic or any other), first - I give myself a few days brake from my every day training.
Before the atempt I do some warm up and streching (especialy my chest).
Then I do 2 negative statics (with passive exhale),
one atempt without fighting too much (till 10 - 20 contractions),
and then I go for my maximum attempt.
My breath-up is:
for about 3 minutes - deep fast inhales, 3-5 sec hold, very long and slow exhales,
3-5 fast, full inhales and exhales,
one inhale with packing, hold for 3-5 sec, max exhale,
inhale with few packs and I go for it.
This is my routine for wet statics.
For dry I simply do 3 attempts with that breath-up before each.
Third one is usualy my max.
I've been in only one competition so far and I did the same preparation like usually before wet max attempts.
When I started my freediving training, about 6 months ago I did PB's every week or so. I just couldn't resist to see how fast I make an advance.

Now I try to do it only once a month.
This routine works for me so far but it doesn't mean that it will work for you. I can only hope that it helps you to find your own.

I'm also curious how do others do that. Maybe it will help me to find something new for myself.