There is no shortcut to these things. You have to work through some textbooks, doing the problems. The Feynman Lectures on Physics are great, and they are free

There is no shortcut to these things. You have to work through some textbooks, doing the problems. The Feynman Lectures on Physics are great, and they are free online. These three volumes will give you a good overview and a taste of what is beautiful and exciting about physics.