P3 is a very practical paper so you need to practice a lot. Spend 30% of your time on learning and understanding the models and the rest in applying that knowledge to scenarios i.e. question practice. You really need to know the model only then you can apply it to a scenario. Don't think that it is important to apply a model. A model can be a useful tool to generate ideas and give your analysis a direction.
There are only few techniques involved requiring numbers such as IRR, NPV, Time Series Analysis etc. These are very important as they may form upto 8 or 10 marks in a question and they usually form a part of 2 or 3 questions in an exam especially the compulsory question. Also read technical articles and examiner's comments. These are important and something from these articles usually does forms part of the exam question.
Complete a syllabus area and practice questions related to that. You'll find your answers not so detailed as the model solutions at the back of texts or revision kits this is for two reasons. First, it is completely ok for different people to use different models to generate ideas so if you use another model than the model answer it is completely fine as long as you justify your reasoning. Second, the whole syllabus is very much inter-related so your answers will seem to improve as you learn and cover more of the syllabus.
To secure your marks for every point you make justify it. e.g. If you are commenting on a particular merger then don't just say that this merger will result in increased profits. This will gain you just half of the mark and you'll lose the remaining marks. So explain your WHY ! e.g in the same scenario you can say that profits will increase as the X Co. will gain more customers and access to a bigger supplier base etc of the company it has merged with.
Keep an eye on the latest news as sometimes the first case study is based on some recent issue/scenario in the business world. Watch programs like Dragon's Den. They sort of give you an idea of how businesses/products are evaluated.
If you keep on practicing questions as you study you won't find it boring as is the perception for P3.