How to stay consistent

So I'm in Grade 10 Icse currently. I have problems staying consistent with my studies. I only study the day before the exam and still manage to get 85%+ in every single exam. I know thats good but I want to stay consistent so that I feel good and don't feel pressurized on the last day of the exam. Any tips for atleast studying like 2-3 hours per day? My weak subject is Physics and Maths. For some reason there is something weird with me If I get really Good In maths I flop in Physics and if I get really good in physics I flop in maths. Any tips for that as well?