You can go to your Wii Shop channel and link your Wii to your Club Nintendo account. You'll get coins if you download a game for a certain time period after it comes out, though what games this works for seems to be kinda random in my case.
A couple weeks before a Nintendo game launches, you can go to Club Nintendo and submit your intent to buy it. You'll get bonus coins when you go to register your new release on Club Nintendo.
A couple months after you register a Nintendo game, you'll be sent a survey for your thoughts on the game after playing it. Another ten coins for filling that out.
I hear you get bonus coins on your birthday, too.
"The worst part about these reviews is they are [subjective]--and their scores often depend on how drunk you got the media at a Street Fighter event." — Mona Hamilton, Capcom Senior VP of Marketing
*Image indefinitely borrowed from BrainBoxLtd without his consent.
