I can speak from a fair amount of academic research experience. First, and absolutely most importantly, you need to consider your prospective sources. They must be credible, lest you lose your own credibility on whatever you are writing. For Internet sources, Wikipedia is a great starting point (and I emphasize "starting point"). It will give you a broad overview on most topics, giving you more specific areas about your topic to further research. Better yet, a well-written and researched Wikipedia article will come with a built-in reference list, often filled with reliable sources which you can use. If this is academic research, never use Wikipedia directly except in the most general sense (and never ever cite it as a source). For other Internet sources, look for domains other than .com. Commercial sites tend to be unreliable, as any person can register this type of site. There are exceptions, of course, but you need to check into the publisher for credibility. .edu sites, in my experience, are the most reliable sites, since much of their information is peer-reviewed before publication. .gov sites also tend to be reliable, and are often best for finding various statistics. Depending on what you're researching, academic journals can be useful, since they're chock-full of peer-reviewed articles. Getting your hands on these may be difficult, but many colleges and universities have free student access to databases of journals and articles.
Second, use effective note-taking while researching. A good paper is not built upon copious amounts of notes, but rather precisely-targeted and well-organized notes. Create an outline of what you want to write and restrict your reading and note taking to information directly pertaining to things in this outline. This will save time, writing, and improve your finished product.
Lastly, don't forget to give credit where credit is due. More likely than not, the majority of what you're writing will be based on the work of others. You need to cite all sources and compile a reference list to be fully compliant with this. It is certainly an intellectual crime, and in some cases actually illegal, to claim another's work as your own.
Purdue's OWL site is probably the best place to look for more tips, but these are the essential steps for good research.