Giving feedback to pupils

I have been trying to give feedback to pupils in the following ways:

1. while pupils are doing seatwork:

• I will go round to check on their work and give immediate notice to pupils as to whether they have done correctly or not;
• especially when they have done wrongly, I will point out their misconceptions or where they have gone wrong;
• normally I don't tell them the correct steps, instead, I will point to them where their mistakes are and ask them questions that will help them to identify their errors which most of the times pupils are able to realise where they have gone wrong (giving pupils the ownership of their own learning)

2. marking their homework or tests:

• as I mark pupils' work, I will be able to identify some common mistakes make by most of them which I will then address as a class when I return their books or tests back to them;
• individually I try to write some comments or questions next to their mistakes to help them understand why the particular part is wrong; e.g. if correct answer is "x^2-12x+5=0" and pupil wrote "x^2-12x+5", I will circle the whole answer, put "=0" at the end and write "you have written down an expression and not an equation".

The above methods are just some ways I am trying to make my feedback to pupils as effective and meaningful as possible. I am still thinking for some better ways of writing down my comments on pupils' work as it is not the usual habits for a math teacher to write comments in a math problem.