if u have not finished the portion then topically is preferred (which i don't like)
but once u finish all the portion
u can start yearly.
and finish many years in a row.
do 10-15 yearly papers (like example 2000-2009), and then check with the markscheme
write down the mark scheme points there with pencil.
this will allow u to ace the subject
and this will help u while revising (u can see ur mistakes and what mark schemes mention)
also sometimes the questions are quite repeated in some subjects, so u can know what answer is preferred through the markscheme.
hope it helped.