Mega mix 54

masquerade
establish

23d disguises oneself as mere squad characters o-s-u-r-d-- 11 letters

There is a "language" of cryptic clues.

Disguises oneself - it's an anagram (also a hint - a masquerade is a disguise.)
Characters = letters
Mere squad = source of letters for anagram
It's kind of fun once you get into it.

Another thing about cryptics is that the real definition is often at one end or another of a clue.

So a clue like Naked woodland creature, we hear is solved like this:

1)There are 2 words that sound alike - that's what 'we hear' means
2) The words at the end are naked woodland, or it's the first word only, naked. Given that naked woodland might be too obscure, it's probably just the first word which is the definition
3) So, what are synonyms for naked? Undressed, nude, plain,and bare (there are probably others but these 4 came to mind quickly)
4) Which of those words sounds just like a kind of woodland creature?
5) It's bare, of course, which sounds like bear
6) Hence the answer is BARE.

https://en.wikipedia.org/wiki/Cryptic_crossword#How_cryptic_clues_work

https://blog.oxforddictionaries.com/2013/04/18/crosswords/

http://puzzles.telegraph.co.uk/site/puzzle_tactics