General tips on marathoning games/ endurance tips

Hey guys! Im new on the forums but have had a passion for retro games for years. Im currently working on a high score for super c on the NES. My question to all the pros out there is do you guys do anything before or during long stretches of time that you have to play games? Like do you drink coffee, have a cigarette etc before begining? Do you stretch, eat a particular food, consume a particular substance (legal of course) or anything like that? And lastly for people who game for hours/days on end how do you do it? How do you keep the focus