Good research is essential to success at any MUN conference, and at any conference it is important to be prepared. Since there is limited lobbying, there is no time to discover what people will be talking about, and so no time for any last minute research at the conference.
Information About The Country
Firstly, you should know the basics about your country; this includes its history, location, politics, demographics, major religions and major exports. You should also research your country's official (or implied) policy on the issues in your committee - it's important that you represent the country as they would represent themselves, not as everyone thinks they would act.
You should think about what all this background about your country tells you about its policy: a country that has very limited exports will likely be very loyal to its trading partners; nations that have experienced a lot of international military intervention won't look favourably on breaches of sovereignty; countries with one dominant religion will tend to be allies with those of the same national religion, and so on. This is a vital way to get a more subtle idea of how your country may behave in debate.
It's always good to research some interesting facts about your nation too - find some nation proverbs or little-known facts about the country to impress people with your knowledge.
Information About The Issues
You must know as much about your issues as possible. However, it is always better to have some knowledge about all the issues than to know everything about just one issue.
In your research, you should make sure you know about any prior action the international community has taken on a subject, the relevant nations and organisations to the issue, and any recent developments in the issue. All these things should help you to form your arguments well and follow other people's arguements. While it's obviously preferable to be able to impress everyone with your comprehensive knowledge of your issues, it's absolutely fine to ask your chairs or fellow delegates what something is - everyone will be happy to help.
Finally you should know as much as you can about the UN and its workings, so you have an idea of the action it takes and the methods it employs. The UN's website also has statements by all the countries (except the DPRK) about their positions on a great many issues, and also general statements about the country.
The UN Website also has all the resolutions passed in the General Assembly. These are important to take a look at as they will often give you ideas on what to write for amendments, although you should never directly plagiarise this content. This is also a useful source for information on other nations' positions on your topics.
Where to Find All This?
We've provided a few useful links to get your research started below. It's also advisable to keep an eye on the news in the run-up to the conference in case of developments, since even an event from the night before the conference will be fair game in debate. Try to use sources biased to your country's position to complement your factual research - national newspapers, opinion columns and press releases are all a great way to get a handle on how your nation views an issue. Furthermore, you can always contact your chairs for any and all advice on your research, or feedback on your resolutions.
Hopefully this will get you started in your research. While it may initially seem overwhelming to have to know everything about everything, the task is far more manageable than it looks. Good luck, and I look forward to seeing you all at the conference!