Bang-on what WASALOADIE said.
Ground school is very intense, and you'll definitely need to study every night. You can (possibly) afford one day per week off from studying. It depends how well you're doing, and how well you absorb the content. I knew people who studied twelve hours per day and still failed five out of seven exams. Many will say that the content isn't difficult, there's just tons of it. The ability to retain information is key.
Although some instructors will disagree (probably because they have to toe the party line), but I'd advise you to start on the question banks as soon as you start the course. As soon as you cover a chapter, refine the topics on Bristol Ground School or AvExam to what you've just covered, and do the questions. Students who didn't use question banks were always the ones with the lowest exam scores. Use question banks wisely, in addition to proper study and learning the content. ONLY using question banks is very, very foolish. To get a really good average you definitely need to know the content, and know your way around how EASA ask the questions.
Personally, I'd just enjoy yourself as much as you can before you start ground school. You won't have much time to do so when you're there. You quite literally live and breathe those exams for six months. In six months I can count on one hand how many days I had without opening a textbook. I don't really see any need to get ahead of the game, as the instructors build you up gradually. Just chill until you get there
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