Though the FAA has never described exactly what constitutes a weather briefing, the requirement remains that a pilot in command must be familiar with all information about a flight. Weather is one of the most important things to familiarize yourself with before a flight. Your EFB has the capability of providing you a high quality weather briefing, and here are a few websites with which you should also become familiar:
Ground knowledge is foundational to flying. Learning the concepts of aerodynamics and the organization of the national airspace system probably does not sound exciting, though it is just as important as establishing flying skill to operate safely. Fortunately, the FAA has published numerous handbooks to provide you with all the information you need, and they're available for free. You may also obtain hardcopies but the FAA does update the content. Follow the link to download them. I recommend the Pilot Handbook of Aeronautical Knowledge, the Airplane Flying Handbook, the Aeronautical Chart User's Guide.
One of the most challenging aspects of flying for many new pilots is the radio. For some it is difficult to understand the terminology, others are intimidated by the fast pace from the controllers, others simply have a difficult time formulating what they want to say before keying the radio. One of the tools which is particularly helpful is LiveATC.net. This website permits you to listen to real-time radio traffic. Listening to this either in the background or intently will help you become familiar with radio traffic for specific airports. Try it out! Pick a busy airport such as KDEN, KAPA, or even KJFK, and listen to the controllers. See if you respond in a way similar to the pilot.
A knowledgeable pilot is a safe pilot. Constantly learning, researching, and testing one's knowledge is important to maintain safe flying habits. One of the best resources of continuing education for pilots is Boldmethod. Check out their quizzes and articles on a variety of subjects.