Researching is the most important part of properly preparing for a conference. It is necessary to know the stance on all the issues the country or organisation you will be representing will debate. You can find a lot of information regarding a nation’s policies on for example the website of the CIA World Factbook.
You can always contact a Student Officer that is in charge of your committee if you have any questions on how to prepare.
The ‘Best Delegate’ website is also really useful for starters, intermediates and experts alike.