To structure the information. For kids who love to play chess and to solve logic tasks easier and faster just to learn the case, if the information about them will be Packed in tables, the information blocks with arrows, notes and underlining. For these children to remember and understand - words-synonyms.
To speak, to ask and to discuss. Alone or in a small group to teach grammar faster and more fun than alone. Dialogue increases understanding information, and hence facilitates memorization. Discussion information unit for a specific case (questions of the end of the three declensions of nouns, characteristics of declensions of numerals, etc.) includes additional cognitive mechanisms.
To create a strong associative link. This means that you need to "blind" case with numbers, colors, smells, sounds, vivid memories. Visual quickly remember the grammatical cases, if personifiziert them will present each of them as individuals. For example, the nominative - an important official or even the Director of the school (this character is more akin to a child's picture of the world), genitive - the father of the family, accusative - a sad little man with his head bowed on his chest or, on the contrary, the severe Prosecutor. If the child will represent them in the form of monsters or amazing animals even better. The creative process will make the memorization process easy, and therefore quick, because the student will not notice how time runs.
To make them tangible. For those children who are accustomed to manual labour, cases must be tangible financially, physically. A parent or teacher can create an associative link, tying them to the buttons on a school uniform, and even better to the fingers. Nominative - the thumb of the right hand. The rest will sit on the left. For a start their names you can write on each finger, and even compose a story about family cases. Thumbs - nominative and genitive - mom and dad. Dad on the other hand - he was at work. Mother in the house with children. Index finger - the eldest son - the dative case and so on. After some time the child will be enough to touch fingers as the memory will revive memories.