Have a schedule. When you're in class learning about a subject, make notes! Those can help you with homework and upcoming tests! Things like my phone, TV and video games distract me and make me less efficient when doing homework, so I avoid being around those things.
Does the writing have a clear sense of purpose? *Is my paper's main idea, or thesis, clearly stated early on (within the first paragraph, ideally)? *Could I organize my ideas more logically (within a paragraph or among paragraphs)?