Try to get a lot of rest the night before. It helps.
Shut off your phones, disconnect your doorbell, and
use music or tv to blot out the noises of the world. lol
Try not to focus on the prize. Stay in the now. Keep
an eye on the average chip count for reference. I've
been well below average count sometimes and still gone
deeper in the field than I thought I would, so it's not
always a given.
These are 5 to 6 hour events, so it's a marathon not a
sprint. If you had more time I'd suggest practicing in
a few of Stars 6000 entrant freerolls. lol Those are
gruelling.
You could always play a SNG the night before, or just do
some reading and studying. Whatever works for you.
Large fields also mean more chances to get beat. Longer
tournaments give you more chances to make a mistake.
Concentration has a tendency to fade in and out after hours
of play sometimes. Thats usually about the time monkeyman
shows up.
Sometimes the cards just don't come either. Sometimes you
aren't playing your best that day, for whatever reason.
Sometimes the poker gods are just against you. Sometimes,
all of the above. lol
I've played in enough large prize events now, either cash or
satellite events to wpt or whatever, to realize that
sometimes it's just out of your control. You can play great
for 4 hours, and make one mistake that wipes it all out.
Just try to pay attention, stay relaxed, get your money in
with premium cards only, and hope for the best. Use position
to your advantage when you can. Try not to play too many
hands. Sometimes adrenalin can do that. heh
Good luck!
