I have a “working backwards” technique for most of the clues. Find the obvious anagrams (e.g. 6down), the crap puns (3 down) and then try to spot the “straight” part of the clue. For instance, I got 10 across by spotting that polo neck is a type of collar, then confirming it because poloneck is made up of the word ‘lone’ (solitary) flanked with the word ‘pock’ (mark)