I'm near the end of Year 11 now.
If there were anything I would advise, it would be this:
1. Do your best not to fall behind in any subject (flopping in Modern History).
2. Focus on weaknesses.
3. Getting a tutor can help if you get one early enough. They can help ALOT and it's better too early than too late.
4. Do what you're good at usually being what you like.
I'll give example of myself if each one:
1. I didn't study much or pay much attention in History this year (TBH), I don't understand the content (Arab-Israeli Conflict) in class anymore.
2. My weakest subject is Modern History and English. I moved from a very poor school (rank ~500 at best) to a rank ~30 school. My rank in the poor school was 20/150 and my new rank in my new school is ~45/150 which was surprising considering I was always crap at it. It turned out that extra focus actually can improve you significantly.
3. My tutor helped me ALOT in English this year. He analysed texts in a way that was different to what was taught at my school so I stood out from the crowd.
4. I don't think I'm any good at History but I have developed a fair bit in English. I think it was a mistake to pick History but my choices were very limited due to lines set, my first preference was 3 sciences, 3U maths, Advanced English but I ended up being "forced" to pick Physics, Chemistry, Modern History, 3U Maths and Advanced English. I enjoy all my subjects although I have a rather poor teacher in Physics (but considered the best in my school). I'm doing rather well in all subjects except Modern where I'm slightly below the median.
I apologise if my examples are abit iffy but I'm tired today.