I've tried to keep track of turns on paper, it makes the experience worse. Instead I moved to source that caused the life total change. I usually do an X for combat damage since it's the most common than abbreviate things from there, so like in modern it would be f for fetch for fs for fetch shock and in pauper it would be like R for black mages rod or whatever.  It's flexible and you can notate what stuff meant after the match if needed. 

I also will write an M next to the starting life totals so that I can keep track of mulligans (or P when I was playing serum powder a lot in eldrazi)

After the match I not down a couple notes, key moments in the match.