A short practice cycle
Predict the output of a short programme. Track variables in a table, then code a related problem and check the output. If your prediction was wrong, record why.
Connect concepts
Connect objects and methods, selection and iteration, class creation and data collections. Revisit an earlier problem whenever you learn a new structure.
A weekly checkpoint
At the end of the week, revisit two earlier mistakes independently. Explain your reasoning as well as the answer. If a mistake persists, review the concept before adding more questions.