Success in DELF depends on applying your knowledge across listening, reading, writing and speaking, not merely memorizing grammar rules. Begin by identifying the level you need and selecting sample tasks designed for that level.
In reading tasks, scan the questions before the text and identify clues that guide your attention. For writing, sketch the key ideas before drafting and reserve a few minutes to review transitions, verb forms and agreement.
A manageable routine combines brief daily listening practice, thematic vocabulary review and a weekly timed task. Record your mistakes by skill so that your next practice session addresses a clear weakness.