Also (not sure if covered) but related: Look at stuff that has been tried and failed in the past, ask why it failed and see if anything has changed in the inte

Also (not sure if covered) but related: Look at stuff that has been tried and failed in the past, ask why it failed and see if anything has changed in the interim that might effect that. Example is dropbox, they weren't the first with the idea of "have a space on your computer that is synced with the internet" but AFAIK they were the first to try it at a time when bandwidth for shifting files around was trivial.