a) If the missing word is at the start of the sentence, ask yourself if a gerund or a participle fits. Many answers are -ing forms or participles (having and being are very frequent).
b) Cambridge loves relative pronouns, the most common one by far is which. Study defining and non-defining relative clauses.
c) 'With' comes up frequently, but so does 'without'. That's why you should read the text as a whole before you start thinking of the answers.
d) 'if' is very common, but so is 'unless'. “Unless” means 'if not', so again, reading the whole text to get if it´s positive or negative.
e) While 'to be' is, naturally, the most common verb and has its own section, other verbs are quite common. For example, 'have' (and has, had, etc) are useful for making perfect tenses. Do is useful for emphatic language.
f) Linking phrases. For example: whereas, although, however, despite, spite (in the phrase in spite of), also, but, so, while, such as...
There are many easy points to get in this part of the exam.
g) Prepositions. The most difficult and boring part of english and the problem is that Cambridge loves prepositions. Look for uses of: in, of, by, out, before, after, at , on…
h) These words also might appear: no, there, once, even, such, since, it, myself (or themselves etc), what, either, and these.
i) I was amazed how many times 'the' was the answer.