Storage. Depending on how big your business gets, you’ll need ample room to store the books. You can’t get lazy or disorganized about it, either. You have to keep the books in good condition, and you need to be able to find them when someone wants them. For instance, if you list a book in “like new” condition, and then the pages get smashed during storage, you’ll be in a bind if someone places an order before you realize what happened.
Get-rich-quick schemes and fad weight-loss diets are naturally popular because they satisfy the id while also attending to the super-ego. The ego's job is complete when it sees something like this. The appeal of "fast'' stems from the innate desire for instant gratification, so beware of what seems too good to be true (they often are) when you're looking to make money quickly. Be wary. Listen to the conversation deep within the confines of your mind and do your best to tame the proverbial beasts.