Embrace the crummy first draft. After you've read your sources, jot down your initial responses. Use abbreviations, casual language, sentence fragments, or whatever else comes easily; you’ll edit later.
Start writing in the middle. Begin with the point that interests you the most, or the counter-argument that's most infuriatingly wrong, or wherever it feels easiest to start. After you've written most of your body paragraphs, then go back and write the introduction.
As you collect your sources, keep a running Works Cited or References list. You don't have to get the formatting perfect, but make sure you have the basic information about which sources you use where.
Distracted? Try a focusing software that will temporarily block games and unhelpful websites.
Save your work often!
Research is iterative. If you can only find a few sources on your topic, try reading those and making some notes on them. Often those initial sources will suggest a way to refine your question, or different words to describe your topic, which can lead you to more sources.
Be prepared to adjust your hypothesis and your outline as you go.
The whole point of research is to inform your thinking, so learn from what you read and revise your argument accordingly.