Use your own words - get the ideas down, not necessarily the fancy phrases. Use understandable, consistent abbreviations . Make up your own if you like - it doesn't matter what you use as long as you can understand them. Formulas, derivations, charts, drawings, lists that the instructor puts on the chalkboard. Leave blank spaces for words, ideas, etc.
Paper is cheap.
At least relatively so. Don't be afraid of blank spaces. Lecturers do get carried away at times, then try to jam a lot of important material into the last 10 minutes. Review your notes as soon after class as possible, but definitely within 24 hours. Fill in the blanks you left during class.