Generally I tend to go over my material fairly casually (re-reading/refining my lecture notes) once a week until about a month before finals begin. After that I folow this basic study plan (This may not work for everyone but it works for me):
(Step 1) Get any coursework that needs finishing finished as soon as possible. In other words, make sure it is done before doing any serious cramming. I've tried juggling coursework and exam preparation in the past and this often lead me into a period of relentless procrastination.
(Step 2) Once I've finished any outstanding coursework, split the rest of my month into study days/rest days. Generally I tend to assign them based on a 1:1 ratio (so for example, day 1 = Study day, day 2 = Rest day, day 3 = Study day etc).
(Step 3) On a study day, do intensive cramming. This entails doing practice exam papers, doing extended reading/revision, etc. I tend to crash if I study for long periods of time though so I take a 30min - 1 hour break whenever I:
(1) Finish a practice exam paper.
(2) Become confident in the topic I'm studying (in which case I move on to a new topic after my break)
(3) Finish at least 1 hour of extended study/reading/revision.
(Step 4) On a rest day, I spend most of my time just relaxing. However, for every 2 hours (give or take 30min) of relaxation I do 30 minutes of relaxed study (reviewing lecture notes, reading topic summaries or academic articles).
(Step 5) Repeat steps 3 & 4 until finals begin.