I am not sure how helpful this is for you, but I think that being prepared to take a break from a question with the intention of coming back to it later is important. Especially with the latter questions e.g. circle geometry involving multiple circles or questions that are flooded with
's and subscripts, the question may not necessarily be hard, but there can be a lot to take in. I find sometimes I can waste time staring into space when the info to unlock the question is right in front of me. Even worse, the time which I do use can also be spent thinking about much time I am wasting. In this case, taking a break and returning to the question can be the best thing to regain a broad picture of the question, especially if the lens through which you are reading the question isnt getting you anywhere.
Leaving a question, with the intent of coming back to it is actually hard to do for two reasons. Firstly if you are used to nornally getting everything right it requires a little bit of humility on your part to admit "I don't know how to do this right now." Secondly, its actually really easy to forget to back to it, or to eat up the time on some other question.
Obviously, the best sort of questions to "take a break" from are the ones which ask you to show a result. Leaving it shouldn't affect how you go with the rest (most of the time), since you can assume the result for the subsequent part. However, for questions which ask you to "Derive an expression for the displacement etc" which is required for the rest of the question, if you find youself stuck - stay on it for a bit longer.
Also, another tip with the that might help you wit the latter questions: always ask youself "why am I being asked to show/ prove/ find this?" and look to make connections with the other parts of the question. Often what stuffs people up in the latter questions isnt necessarily their algebra skills or lack of content knowledge, but their llack of ability to make connections between, say, Q8a) ii) and b) iii) etc. Remember, not every question needs to be prefaced with "Hence or otherwise" for you