How do you get a lot of trophy stands in Super Smash Bros.. Brawl?

You need to be lucky. Trophy Stands are only available in Subspace, and you must beat some enemies up. The Trophy Stand is a drop item. If you want a Trophy Stand against a boss, you must be really lucky and hope it's a drop item. You'll get a higher chance of obtaining a Trophy Stand either way if you're playing on a higher difficulty, so try out Intense or Very Hard for the best chances.