Hi, I'm going to Japan on Saturday. Is there anything I should know before leaving such as how to act, eating, etc.?

Where are you going?

Don't blow your nose at the table (...I hate that...).

Oh yeah, where are you going?

Don't stick the waribashi up your nose and do walrus impersonations before at least 11PM.

just be yourself and they'll forgive you for being a foreigner.

some tips though, pretty much same as the west:
* don't jaywalk.
* do ask for a fork if your chopstick skills will force you to eat with your fingers.
* do burp as loud as possible after eating while rubbing and exposing your stomach (kidding. dont do that.)
* stay to the left side on a busy sidewalk.
* don't litter.

different from west:
* don't tip.
* don't try to hug someone unless both of you are drunk.
* don't walk on tatame with shoes on.
* don't try to navigate the subway/bus system without help....you'll end up lost.

have fun.

I'm going to Yokohama but I'll be spending two days in Kyoto and 1 day in Tokyo.

I'd recommend several more days in Kyoto if you could. You really should hit Nara as well.

Don't talk to strangers unless you're trying to pick up a girlfriend. If you're trying to do that well, you're on your own. Look up nanpa.

It's ok to slurp ramen. But don't spill it all over yourself.

Don't pour soy sauce into a bowl of rice. However normal you think it is, it's not!

Don't pass food with the end of chopsticks you just ate with, that's gross. Use the back end.

Try to use Japanese when you can. You'll be popular just for trying.

Get a JR rail pass. You can pick one up for between 20 and 60 bucks USD. Here's the page in English. Make sure you have the right visa, they aren't kidding about the temporary visitor thing. http://www.japanrailpass.net/eng/en003.html

Well whatever, it worked for me