A good lesson plan starts with one clear, measurable objective -- 'students will be able to...' followed by an observable action, not a vague goal like 'understand fractions.' From there, a lesson typically follows four phases: a short opening that activates prior knowledge or hooks interest, direct instruction where new content is introduced, guided or independent practice where students apply it, and a closure that ties the lesson back to the objective. Skipping practice or closure is the most common planning mistake -- students who only watch or listen rarely retain the material. Every lesson should also include at least one quick formative check (a question, a show-of-hands, a one-minute written answer) so the teacher knows, before moving on, whether the objective was actually met.