To all A level Physics students:
the key concept to Physics is just about forces. Nothing but forces.
Look at your Mechanics. Kinematics is about acceleration which comes from forces (F = ma). Dynamics and forces are obviously on forces. Moments is about the turning effect of the force. Circular Motion is about the centripetal force. Oscillations is about the how the force is always opposite to the displacement. Gravitation is about forces of gravity.
Remember force is a vector, and it can be resolved into at least 2 directions. (Brush up your basic trigo).
Physics in a Nutshell for Os and As
When in doubt, just resolve into parallel and perpendicular directions, then resolve all forces in the parallel direction, resolve all forces in the peprpendicular directions, then finally vector sum them together using pygathoras theorem and trigo.
Do try to see the general picture of Physics, and understand it through forces and vectors. Most of the topics are inter-linked, and if you can catch this general gist, you will be able to do most of the questions.
Next portion of Physics: Understanding how to draw the Free Body Diagram
When you know how to draw and understand Free Body Diagrams, as well as resolve the forces involved, the door to solving Physics questions will be opened.