My preferred method would be Nembutal ....but I have no idea where to obtain it. There are many many scammers out there so chances are I'd just lose money and that's all. Hanging is another possibility and it doesn't need to be full suspension. Many have done it just hanging from a door knob / door handle and kneeling / slumping down. Or knocking a nail into the top of a door, attaching a noose and... probably unconscious in seconds.
Then there is starvation and hypothermia. With starvation the worst hunger pangs are over in the first few days. But it can take several weeks.
With hypothermia you just need to go somewhere freezing cold with something to lay down on, strip down to underwear and overnight you will die. Alcohol would speed up death by increasing blood supply to your capillaries and lowering your core temperature quicker. And it would look like you got drunk, stripped off because you were drunk and not necessarily suicide. You could always light a fire the day before and deliberately put it out so that when discovered it looks like an accident or misadventure in that the fire went out that night and you froze to death. My only concern would be animals scavenging my corpse or if they did that before I was truly dead.
I suppose renting a log cabin for a few days and leaving the windows open would be one way around that. Would need to be somewhere like Norway or Alaska or Switzerland and in the winter. You would shake violently, then the shaking stop and then you would feel warm although you aren't warm and then pass into unconsciousness...