I suggest you allocate the whole week for correction. The first session try to prepare a worksheet with remedial activities ie see what your pupils failed in and prepare an activity for that purpose.I tested my pupils on past progressive but I noticed that more than half the class still not master and make the difference between S.past and P.progressive so I prepared a worksheet with the rules and an activity about s.p/p.p. . The second session try to correct the essay. Make sure you take note while correcting of all the reoccurent mistakes done by the pupils.Try to prepare a second worksheet with two column one for the mistakes and try with the learners to correct them. I also suggest you take a sample suggested by an average pupil and photocopy it then put the learners in groups of four and have them identify mistakes and try to correct them together. At the end , have  good pupils read their own essays to the class ; you �ll see how they will appreciate that (specially if you �re dealing with young learners) hope this can help.

NB:different inspectors may suggest different things and ways to correct tests but this has worked with my pupils hope it �ll work with yours .