You can further refine learning objectives by stating the condition under which the behavior will be carried out and the degree of performance that will achieve a passing grade. For example, "Students will be able to demonstrate knowledge of ____ by reciting from memory" or "with the use of notes" establishes the condition. "Students will be able to demonstrate knowledge of ____ by recitation from memory with 80% accuracy" establishes the degree. The degree will form the basis of your evaluation.
This simple formula can help you determine what knowledge students must know at the end of each lesson, how they will demonstrate that they know it, and what degree of performance you will regard as sufficient to demonstrate successful learning.
Whether you use this specific form of objective or some other, you should always frame them in student centered terms, focus on what students will know and be able to do, and check to see that each portion of every lesson is keyed to one or more of your objectives. You should formulate objectives very carefully, since they will shape the lesson you teach. Successful lessons must teach to the objectives.