1. The first thing you should do is read introductory books on investing. Since your in college, I would recommend that you become interested in swing trading (holding positions for several days or several weeks) rather than long-term investing or day trading. You won't have enough time for day trading because you will be busy studying and won't be able to view the computer from 9:30 AM to 4 PM.
2. Decide what investment vehicle/market you are interested in (stocks, bonds, futures, forex, etc.). I would recommend stocks because they are the most popular and there is a ton of literature on the topic. While it is good to study all markets, you should specifically focus on one. Furthermore, if you pick the stock market, pick a niche/sector to specifically analyze. This is what most successful traders do.
3. Paper trade with play money (simulate trades... you can use investopedia.com for example). It's not totally realistic because of slippage and the risk you are willing to tolerate, but it is a start.
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So if you are new, read as much as you can. I recommend that you click on the books page here on elitetrader.com Review the ratings of the books and purchase those that you think will be most interesting. Personally, I would start with those listed on the "Classics" section. Pit Bull and Trader Vic are great introductory books and they read like novels somewhat. You will find books on trading incredibly repetitive. Each one will have something to contribute nevertheless, some more than others. If your on a tight budget, purchase used ones with the best ratings. Another option is just to goggle the topic on the web. Use the search in elite traders. Go to the Noobs section!
BTW, there are many books not listed on this site. Just go to amazon.com and search for books related to trading. Make sure the are not about long-term investing because that is another game.
Just by spending a hour or so daily on elitetrader.com you will also learn a lot. Be aware that the majority of ET members are not proftible. Many people here have crazy opinions. NEVER trade with real money because it recommended a stock or whatever on a thread. Just read and observe. Eventually you'll have enough knowledge to make your own comments about a particular stock or the economy. So take everything on this site with a grain of salt.