Your single most important tip for 1st time high Buy-In MTT

Play to win and not think about the prize money . That would psychologically not feel the extra pressure of the tournament . Use positions well . Start tight , and push the options more actively for the blinds in the middle and later stages

Ok If You wanna just one advice, play only with a position.

Don't you think that when you play high stakes mtt players don't bluff for that reason they start bluffing more often