As I have no experience in trading futures, I think doing some background research on the corn, wheat and soybean market is necessary.
Here is one concise and simple webpage about corn trading; http://www.tradertech.com/information/corntrading.asp
It not only states about where are the corns grown but also mentions about what are the corns used for. Corn is important because it is an essential food source for livestock. Hence, the monitoring of animal numbers could gauge the scale of corn usage during the season. One webpage we could visit for information on cattle ranching is http://www.cattlenetwork.com/.
Secondly, corn is becoming an important source of fuel because of the increasing utilization of ethanol in gasoline. Hence, observing the developments and changes in the energy market may shed some lights on corn prices. From one point of view, high oil prices imply high corn prices. However, if we look at the other side of the story, high oil prices also suggests that there will be less demand for gasoline and the need for ethanol especially during recession. The ethanol producer magazine website could give us valuable information on the latest developments in the area. http://www.ethanolproducer.com/
I also found a website with up-to-date and comprehensive news on agricultural commodities. I believe that reading the website everyday would definitely give me some enlightenment on what to do in the trading game when I feel confused or could give me some explanations when the market acts against my actions.