I once tried to calculate how much vodka I would need to drink to kill myself. It's a bit difficult though, cuz the only data I could find is for animals. I thought maybe the animal most similar to humans is the rat

so based on the LD50 of ethanol for rats, I decided I would need to drink pretty much an entire 1.5 L bottle of vodka to make sure I didn't just wake up with half a brain and the hangover from hell. Problem is, I would probably pass out before I could get that much vodka down my gullet. Conclusion: No good.
Then I thought about wrist-slitting. There is quite a science to that method also. You need to make sure your blood vessels are relaxed and dilated, so the blood flows out nicely. Best thing is a nice, hot bath, while drinking some alcohol to dilate further and soothe the jitters. A very sharp blade is needed - best to go with an Xacto knife, I would say - the handle makes it easier to use than a razor blade. Then the actual incisions - this is tricky. You don't want to cut crosswise, cuz the severed tendons render one hand useless. At that point you can't even use it to slice the other wrist, so you've left the job half-done. You need to slice lengthwise to get a good-sized incision - and btw, the skin slips over the top of the artery, and it's not as easy to slice living tissue as you might expect, so since you can't really practice this sort of thing very well, it's probably going to take some trial and error to actually get the artery on both wrists sliced and flowing - especially since by now you're a bit drunk from the alcohol. And of course, you hafta hope you've done an adequate job on the dilation bit, otherwise you'll wake up in a stinkin psych ward, where they'll make your life even more of a hell than it was before...
I could go on and on, but I think I've already overused my allocated space in this thread.