Physics can be difficult if an effort to learn it is not made. You will need to make a consistent effort. Start by learning the theory well before you do numerical
Making mental pictures of concepts as you study them and imagining the possibilities can really speed up your understanding of it.
Visualize Physics
Often the derivation itself gives great clarity around the topic and the numerical problems you will attempt.
Learn to deconstruct a numerical problem - Making neat diagrams and putting all the available information around it can accelerate you towards writing the correct equations.
Be disciplined about not "rushing through" when solving a numerical problem. In other words, do not jump steps while doing a problem.
Particular integral and differential calculus, in place. It will be required for solving numerical problems