Sometimes you'll find that you can get the correct answer all the time on papers but then lose marks on method marks. I'm a B grade student too and happy with where I am, as it took lots of getting used to the Edexcel papers to get where I am and had external help too. I was encouraged in Year 9 that as I developed confidence with calculations, to slowly take out steps so my method is clear and simpler. However, I've begun to notice that this isn't helpful at all. You have to write EVERYTHING. Even if you do 2-1 in your head, write it all down. You can pick up marks and looking out for that is really good too.
I know mymaths has been suggested before, but I despise it and so do my friends. It only checks if your answer is correct, not your method. Which means you can get into really bad habits of skipping key stages of working out. I find mrbartonmaths.co.uk (or.com?) useful too, the maths takeaway has each module broken down with a 3 page paper and answers are included. I use this to check to see where I tend to go astray with my method. However, my computer detects viruses on it so I advise you to be careful if you don't have a virus software installed.
I wish you the best of luck.