In order of importance, curriculum, motivation, academic ability, and teaching methods are described in this paper as principles affecting classroom learning that can lead to more effective instruction. Curriculum simply exposes students to appropriate content and subject matter. Educational research should concentrate on the evaluation of curriculum innovation, including recommendations to scrap irrelevant subjects in high school curriculums. The second principle is motivation (whether extrinsic or intrinsic) which is essential for classroom learning even when there is a good curriculum. The third principle of learning is academic ability. Intelligence is not highly changeable but neither is it fixed. The teacher should assume a positive attitude toward learning problems as she attempts to be effective. Less important than the others is the fourth principle, teaching methods, which only slightly affects subject matter proficiency. Research should be directed toward finding teaching techniques that minimize time and money expenditure, without regard for effectiveness. Selective use of appropriate reinforcements to shape learning behavior is recommended. (MH)