If you study a little bit every day you’ll be continually reviewing things in your mind. This helps you understand things. It also helps you avoid the stress of last-minute cramming.
Early in the year an hour or two a night might be enough to stay on top of things. Later in the year you might need to study more each day.
If you’re finding it hard to find time to study, cut back on some (but not all!) of your other activities. Prioritising study might mean spending less time online, or it might mean cutting back on shifts at work, or giving weekend sport a miss for a while.