the best advice I was given was get to PyP then think the starts. Don't hammer the descents until Lliwedd, almost treat it as a training run until PYP, then go for it. If you blow up on the Peris you'll lose time like in no other race because it's such a technical steep second half.
Mentally you also get a lift from passing people lay on the ground cramping up or walking and stopping on walking climbing the east ridge of snowdon.