They use PCLM. P is Purpose (how well you answered the question), C is coherence (the overall flow of your piece), L is language (your vocab, syntax, and incorporating the different styles of language), and M is Mechanics (grammar, spellings, punctuation). The P,C and L parts are worth 30% no matter what the question's marks are and Mechanics is 10%. So example, 50 mark q = 15 marks each for PCL and 5 for M. This is the marking scheme for every LC English question regardless of marks.
You can't really mark your own papers in English because there is no set in stone right answer... If you answer the question asked with a different opinion to someone else, one answer isn't necessarily any better than the other as long as both opinions are backed up with reference to the text or quotes etc.
Hope this helps and may the odds be ever in your favour!