It would help to know how long you plan to play. The strategy is different for 1 month, 6 months, 3 years, or 60 years.
If I were playing for 1 month, I'd make huge bets that the stock market will go down because September is statistically a bad month. On a very short-term basis the stock market is oversold, so I would dollar cost average in, buying puts if the rules allowed it, or shorting stocks and ETFs if the rules don't allow options but do allow shorts, and buying double inverse ETFs if both options and shorts are not allowed. This is gambling, not investing, but if it's a contest with play money the way to win is take a guess and leverage to the max.
For a long-term game, I would play the megatrends of the world running out of water and inflation in the US. Obviously the current worry is deflation, but whenever the recession/depression ends, the stage is set for major inflation. Barrick would do well here and is probably the best of the gold "blue chips." GDX and GDXJ are two ETFs to play the trend more broadly. I plan to concentrate more on silver than gold, for two reasons. First, there is no question that industrial demand will rise when the economy grows, and second, I think the price of silver has been manipulated downward, and that can't last forever. Most people would consider the second reason to be totally loony but the evidence is there. The only silver mining ETF I know of is SIL. SLW is my favorite silver stock play.
There are a lot of water plays. I'm following FLS, BMI, WTS, PNR, CCC, and WTR. PHO is a water ETF.
Alternative energy stocks are not in fashion right now, but when oil goes over $100 they will start moving again. Too many choices to list, but these three companies are now in terrible shape, and if they turn things around they will multiply in price: ESLR, FCEL, and BLDP.
Good luck, and congratulations on learning about investing early, when it can do you the most good.
Houyhnhnm