Any information that doesn’t fit within the framework of your outline, and doesn’t directly support your thesis statement, no matter how interesting, doesn’t belong in your research paper. Keep your focus narrow and avoid the kitchen sink approach.
You know, the one where you throw in every bit of interesting research you uncovered, including the fungal growth in the U-joint of your kitchen sink? Everything you learn may be fascinating, but not all of it is going to be relevant to your paper.
A proposal is a persuasive piece meant to convince its audience of the value of a research project. Think of the proposal as the pitch and the paper as the finished product.
Once you reread your first draft over and over and make the necessary changes you feel you should make, it is time to write your final draft. Make sure that all the vital information is included and your paragraphs and sentences make sense and has a steady and natural flow all throughout.
You can find articles testifying that all three of the previous claims are true; however, when you dig deeper, it’s clear that they’re not. Just because you find one article stating that something is true, that does not necessarily mean it is a proven fact that you can use in your research.