Questions

What places should I visit?

major landmarks?
meiji shrine in harajuku, temple in asakusa
roppongi hills

just go to all the major spots: shinjuku, shibuya, harajuku, omotesando, daikanyama
roppongi

Do the rail lines take credit cards?

u should invest in a pasmo
its this card
u have to pay 500 yen to make it
but u can keep recharging it
and thats the easiest way to get around
http://www.pasmo.co.jp/en/index.html


unfortunately jp is very cash society
so trains and stuff are cash only
i believe