I would urge you not to try to learn tricks for a given aircraft as one of the main aims of the course is to give you generic skills of use out in the Industry.

Simplest way to sort out what you need to do is to plot the starting point on the envelope (preferably wt x IU but wt x CG will give you a sufficient idea to see where you need to go). Then, knowing the loading station you are going to use or consider, plot a load point to check where the CG is going and that will identify whether you have a forward or aft CG problem. Unless the examiner is having an off day, he is not going to make it so easy that the answer is blatantly obvious.

Sure, you can learn a set of rules for a given aircraft but it doesn't transfer to the next aircraft .... you need to have generic tools in your pilot bag of tricks.

John's advice is sound. The first thing to do is reach for the CofG envelope and do a quick plot of the present weight and moment given in the question. Doesn't have to be super accurate, you just need an idea of where you are to start with.

The examiner will always tell you whether you are shifting, adding or subtracting weight and which compartments he wants you to use.

He really has to do that, otherwise there would be multiple correct answers to the same question. So, for example, if you are in the envelope but near the forward limit, there will be a limit to the amount of weight you can shift forward, add to a forward compartment or subtract from rear compartment.

The key is to establish the location of the present CofG on the envelope, then read what he is asking you to do.