Monopolizing Market Crashers

Market Crashers is easily the shortest of the third bundle of games, and both the concept and gameplay are simple enough to reduce the amount of manipulation to basically nonexistent levels.  So instead, here's some gameplay tips.

1. You absolutely want as many people as you can get for this game.  Having more analysts available will give you more accurate information about what each stock is going to do, both before trading and while trading.  Make use of the Plaza Update 5.0's new "Send to Line" feature if you're at a convention or in Japan or something to make sure you've got ten, and if you just can't get to ten, top off with Play Coins.
2. The mantra to remember while trading is indeed "buy low, sell high".  It's the only way to actually make money.
3. While you can do longer-term investments in this game, I don't recommend it.  Keep your portfolio empty between sessions and just do Day Trading.  The stocks fluctuate way too much for long-term investments to be worth anything at all.
4. The ability to buy outside of Day Trading can still be useful though.  If your analysts say a stock's value is going to rise, you can get a bit of extra cash by having shares of multiple stocks purchased while you actively trade one company.  You can also buy some shares of the company you intend to trade during Day Trading, so that you have something to sell on that first peak.
5. Buy the new products as they come out, but make sure to leave yourself enough money to continue trading stocks when doing so.
6. Never ever sell the products.  Just keep them.  They still count towards your total assets, but they represent assets you can never lose, except voluntarily if you're absolutely strapped for cash and have no other choice.
7. While the ultimate goal of this game is to become as rich as the guy they tell you about in the beginning, you get the second hat much, much earlier than that point.  If you don't really find this game to be fun, then keep in mind that it doesn't take very long to get the hat.
8. Ace Trader can be difficult to obtain for a given company, as it doesn't seem to be dependent on a specific threshold that I've been able to notice.  All I can say is that if you do the "buy low, sell high" thing very aggressively, you stand a really good chance of getting Ace Trader.
9. The more you trade a specific company's stock, the more of it you'll be able to buy or sell in one press of a button.  This amount is entirely company-specific, so if you neglect one, you'll be buying a smaller number of shares of it the next time you trade it.  This can actually be useful if you run low on money, since that smaller number of shares will cost you less.
10. Don't ask me about the weird graph with the boxes and lines, I don't understand it either.  Just use the simpler one, it hasn't failed me yet.

I hope this post helps all of you aspiring investors make some money.