What OP is asking for is really a bit specialist for this forum.
It's a long time since I've had to think about such things and I might well be out of date but the marks schemes usually have a clear allocation of marks for knowledge and evaluation.
The 'knowledge' is usually just standard drawing curves, maybe pushing them around a bit - e.g. (if asked to describe the impact of say a subsidy) 'there'll be a rightward shift of the supply curve, meaning in terms of changes the equilibrium price will go down and equilibrium quantity sold will go up', or whatever.
Evaluation is trickier. A good way to do it is by learning a kind of checklist of things to consider, possibly using a mnemonic of some kind. What the examiner is testing is something like whether the changes you've described under knowledge will be big or small changes; slow or fast; transient or lasting; and how sure you are about them or whether there are arguments in the other direction.
Candidates for such a checklist might include [there are a couple more - and this list is probably a little better for micro than macro questions]:
Magnitude - i.e. are we talking about a big or small shift of the supply curve... if it's maybe a comprehension type question there'll maybe be a clue about whether it's say a big subsidy or not... e.g. if it's in the billions or whatever you might infer that it is, if it's say a £60m subsidy and it's for the whole country then you might reason that it's less than £1 per person, so not so much...
Elasticity - we said that the equilibrium price will go up down, but will it go up a little or a lot... depends on the slope of the demand curve... need to go back to the early year 12 determinants of elasticity [e.g. availability of substitutes etc]
Timing - will the subsidy and changes happen right away or slowly, will it last for a long time... maybe there'll be clues in the text or something, e.g. maybe there's a huge construction project that needs to happen before there's an impact or...
Conflict - are there any counter arguments to the above or e.g. external forces pushing things the other way... e.g. is the backdrop one in which is supply naturally contracting for other reasons or...?