Reading the Visa thread is best for getting as much information regarding going to Japan. But to promptly answer your question regarding visting; Yes you can visit Japan, American citizens get a 90 day tourist visa. So for 90 days you can travel within Japan, but you cannot engage in work activities.

Also what you previously said about working in Bars/Resturants. Again, those types of work would fall under Working Holiday Visa (which i mentioned in your previous thread). Regarding being an Artist, it requires a Work Visa so it would also very likely require Sponsorship from a company/college and also alot of preparation portfolio work, excellent references etc

Teaching English is one of the widely more chosen professions for foreigners because:
a) You don't need a specific degree to acquire the visa (you still need a degree though)
b) It's one of the few jobs that you don't require any particular knowledge of the Japanese language. While it helps, it isn't usually a pre-requisite

Also as i said above, you have to consider the point that besides the few exceptions, you need to have high knowledge of the Japanese language before you can apply for work. And proper structured knowledge of the language too.