Thank you for the opportunity to help you with your question!
1.Developing a reading habit- Reading keeps your brain busy and active hence increasing your level of alertness besides keeping you sharp. As you read, you brain understands how to work fast and make reasonable judgements within a short time hence improving your concentration level.
2.Solving Crossword puzzles and Sudoku- Puzzles keep your mind working as your try to come up with words that will complete the spaces in the puzzle. Solving puzzles enhances memory, improves concentration and increases your level of alertness.
3.Exam Questions- Answering examination questions improves your memory and alertness levels. Examinations can be self assessed or those given by learning institutions.
Please let me know if you need any clarification. I'm always happy to answer your questions.