20+ year online player who loves and plays mostly longer format MTT's. When a play bigger stake MTT/events like $10-$215 buy-ins....a good night's rest so be well rested and I personally save taking my shower till maybe 30mins before the MTT starts. I find the shower helps me with the rested, refreshed and clean feeling. Other than that, just the normal engery drinks, chocolate and stuff for snacks to keep hungry at bay. Fwiw I'm also not your normal person as I can get by on 4-5 hours asleep a night and still be highly functioning. Most people need their full 8 hours and some could much more lol.
Now if I'm playing micro's and anything under $10 I don't worry about the full night's rest or the shower if there's no time and I'm just getting home from work, shopping or whatever. I'll just grab a coffee or engery drink and jump in.
I'll be interested to hear others tricks and advice. Always open to new ideas and new things to try.
Cheers!!!