Everyone has different methodologies when it comes to Paper C, but a few things are certain. You should start with reading the claims of A1, A1 and the client’s letter.

Claims:

When checking the claims, you will see if there are any “or” or “and/or” in them, which would mean more embodiments, thus more attacks than the number of claims.
For example:
Claim 1: Product X.
Claim 2: Product X according to claim 1, wherein X comprises Y and/or Z.
Claim 3: Product X according to claim 1, wherein X comprises W.
Claim 4: Product X according to claim 1 or 3, wherein X is something.
In this case, you would have thought - before preparing for the Paper C - that these are 4 claims, so 4 attacks are required, but in fact, this claim set includes 7 different versions, so 7 attacks are required:
1. Claim 1,
2. Claim 2+1 comprising Y
3. Claim 2+1 comprising Z
4. Claim 2+1 comprising Y+Z
5. Claim 3+1
6. Claim 4+3+1
7. Claim 4+1

It is very important that all of these 7 versions can have different effective dates and different closest prior arts! It can also happen that the three alternatives of claim 2 have three completely different attacks (one added subject matter, one novelty and one inventive step).

When you read the claims, you should also look for important phrases, such as “comprises” or “consists of”. Also circle/underline any non-technical (e.g. “coloured design” on the cup like in 2007 Paper C), optional (“preferably”, “for example”, “more particularly”), unclear or relative terms (“strong”, “thin” or “hot”) and “for” (“for” normally means “suitable for” except in first and second medical use claims). You will need to look for definitions how to understand the relative terms, otherwise it might be that you can translate them broadly or disregard them in an inventive step attack (if you do, you still have to mention why you can disregard it!). When it comes to optional terms, they do not have any limiting effect, so the feature following that word is optional (you still have to explain in your answer why you can disregard it!). The features in the claims will have their technical effects explicitly mentioned in A1, you will always have to cite it (and provide the paragraph number from A1) in the problem-solution approach.

Effective dates and prior art documents:

The client’s letter will help you analyse the priority situation, will include any information about added subject matter as well. (Obviously, since this is an artificial exam, you have no chance to discuss the case with the client.) After reading the letter and carefully double checking the information (is that really added subject matter what the client says, or did it have basis in the application?), you should note the effective dates of each claims (and all versions of the claims). You can start writing the effective dates in your answer, since it is worth marks.

You have to be careful when comparing the content of the different documents. When comparing the content of the priority application and the filed version of A1, you are checking the effective date of the claims. When comparing the content of the filed version and the granted version, you are trying to figure out if there is an Art.123(2) EPC attack.

(If something was not disclosed in the priority application and does not have any basis there, the effective date will be the filing date of A1. Unless, of course, it was added only after filing, during examination. In that case, it will not have an effective date and you can perform an added subject matter attack.)

Then, going through the dates of the Annexes, you will be able to decide which prior art can be used against which claims. It often happens that there are documents that can be used against only some of the claims. Furthermore, same document may be an Art. 54(2) and (3) at the same time for different claims. There might be some PCT or EP documents that are Art.54(3) documents for at least some of the claims. If there are any prior art documents with the same applicant as A1, check whether it is the first application, because it might mean that the priority is invalidly claimed for at least some claims. You should summarize the documents and their usability in your answer, since it also gains points. If a document is a written disclosure/advertisement/article etc., you should shortly mention why you can use that document.

Make some notes about the Art.54(3) documents for yourself so that you do not use them for inventive step attacks!

Attacks:

Then you can go ahead and read the Annexes in any order you wish (or your methodology dictates).

You have to perform one strong attack against each claim, more precisely, against each embodiment in the claims. You can expect about 6-10 attacks in the exam (there were 7-9 attacks in the recent exams). Do not forget to write out all steps in your argument, because arguments gain the most marks. Do not miss explaining why, for example, the narrow range is not novel over the broad range (its endpoints are not far removed, etc.). Reasons must be given for each statement. Always cite where you found the information that you are using.

Possible attacks:

• Added subject matter - Art.100(c) (based on Art.123(2), Art.76(1) EPC or Art.61(2))–> usually 0-1 attack in an exam

• Novelty attack - Art.54(3) –> usually 1-2 attacks in an exam

• Strong novelty attack - Art.54(2) –> usually 1-2 attacks in an exam

• Inventive step attack - Art.56 (never use Art.54(3) documents!) –> usually 4-6 attacks in an exam

• Industrial applicability - Art.57 –> very rare

• Excluded under Art.53 –> very rare

• Not an invention under Art.52 –> very rare

Attacks based on Art.100(b) (insufficient disclosure) are not allowed in the EQE!

Although you probably know, do not forget that unity (Art.82) and clarity (Art.84), for example, are not grounds for opposition. So, you do not need to concern yourself if there are more independent claims in the same category. Just attack them using something from the list above. If you use unity, you will probably fail.

It is a good idea to start with a novelty attack, since it takes less time to write it but it is relatively easy to get marks with it.

As mentioned above, inventive step is the most important part of Paper C. You have to practice problem-solution approach a lot, and be confident how to find the closest prior art. (As also mentioned before, inventive step attacks starting from a wrong closest prior art are usually worth zero marks! They usually phrase the documents such that there can be only one closest prior art.) Also, do not write general sentences, but use the information given in the Annexes, and always cite where you found the information. For the technical effect, you should always cite A1.

I will not go into the details of problem-solution approach, since there are way better sources for that.

A final advice: do not forget to thoroughly read the Examiners Report after each of your attempt.