Hi! I did the IPC in year 10 and 11 and both got gold, in year11 I got 45/50. I would first make sure to know the key components of the GCSE course (which you may not have not done yet), such as momentum. I don't think I did a lot of past papers or preparation to be honest, a lot of it is just problem solving skills. You also need to have a solid understanding of a lot of mathematical concepts. You may want to get some UKMT books. Most of the section C are based on maths anyway, so you will need to have a very solid mathematical background - this will also help the problem solving. Familiarise yourself with the small angle formulae like sin(x) approximates to tan(x) which approximates to (x). Also, knowing the radian measures are also very useful, you can get free A Level textbooks or videos on Youtube about these.
For section A, just do your best - they are just multiple choice. There are often really obvious solutions which you can eliminate. I found it much easier to just eliminate by plugging some numbers in and working out which ones were nonsense and then just taking a guess.
For section B, the questions are usually based off a singular equation, such as F=ma or a momentum equation. Sometimes they are based off the properties of certain physical measurements such as current and voltage (there was a question about circuits and why an ideal voltmeter should have infinite voltage). For these ones, you want to identify which equation they want you to use and apply to the death (literally). If you don't know where to start, write as many true things that are relevant to the question, and you will be able to pick up some marks this way.
For section C, (this is going to sound really obvious) but READ THE QUESTION!!!!! A lot of candidates miss pieces of information out that is given in the question. Some of the questions also drop really useful hints such as telling you that something is 'very far away' - assume it is infinitely far away. There are also quite a few proof questions, and in the next questions they ask you something which almost implies what you should be doing the question prior.
I'm not sure if this was very useful... but I hope it was! Good luck, you will smash it!