To improve prealgebra skills, several online resources are recommended, including Khan Academy for a range of math topics and Desmos for graphing. A specific website, Math Only Math, has been highlighted as a useful tool for practice. Additionally, an Indian site offers free e-books and course materials for secondary mathematics. The importance of consistent practice is emphasized, with a suggestion to dedicate one hour daily to study. Finding the right time to practice is crucial for effective learning and preparation for tests.