"Words fascinate me. They always have. For me, browsing in a dictionary is like being turned loose in a bank." ~Eddie Cantor
"Leo (President's Chief of Staff): Margaret. Please call the editor of the New York Times crossword and tell him that Khaddafi is spelled with an h, and two d’s, and isn’t a seven letter word for anything.
...
Leo: [on the phone] 17 across. Yes, 17 across is wrong... You're spelling his name wrong... What's my name? My name doesn't matter. I am just an ordinary citizen who relies on the Times crossword for stimulation. And I'm telling you that I met the man twice. And I recommended a pre-emptive Exocet missile strike against his air force, so I think I know how...
C.J.: [in shock] Leo!
Leo: [looking at the phone, then hanging up] They hang up on me every time.
C.J: That's almost hard to believe." ~West Wing (Pilot)
"A guy doing a crossword in a pub turns to his pal and says 'how do you spell paint'?
His mate thinks for a second and replies 'what colour'?"
"Crossword Fan: I've been trying to think of a word for two weeks!
Friend: How about a fortnight?"
"'Speak English!' said the Eaglet. 'I don't know the meaning of half those long words, and I don't believe you do either!'" ~Alice in Wonderland
OREO is sometimes called the pseudo-official cookie of the crossword puzzle because its vowels help the constructor with ease of crossing words; also because it's black and white -- and similar in age? (to right, "Name that Decade" Jeopardy question)
Summary: read a lot; learn vocabulary, (vowel-heavy) 'repeaters' (e.g., area, aria, oreo), and 'crosswordese' ("words frequently found in crossword puzzles but seldom found in everyday conversation") -- by osmosis or from lists
the answer may be a phrase, rather than a single word -- if so, plural or verb tense in clue might affect the phrase before its end
also know what you (usually) will not find: profanity, sad or disturbing topics, or overly explicit answers
recognize letter sequences: tictactoe (O,X), 'alphabetic trio', Roman numerals, time zones, compass dir., phone keypad, cable networks, ...