1) Highlight useless words like "just" and "that." Delete most instances.
2) Look for redundancies
A) redundant phrases--she bit her lip, she flipped her hair, his eyebrows raised, he rolled his eyes)
B) redundant descriptions--are we getting a play-by-play of every outfit the mc wears, of the love interest's crooked smile, her frizzy brown hair mentioned every other chapter. The reader will remember that the mc has frizzy hair without being constantly reminded
C) Redundant emotions-- "Jenny covered her face and slid down the door after realizing that everyone had seen her skirt tucked into her underwear. She was so embarrassed " Take away any telling things like: she was so embarrassed. We were just shown it, we don't need to be told it, too.
D) Redundant scenes-- If you've already established something, you don't have to keep reestablishing it. If Jenny sees Mac hauling hay and is impressed by his shoulders, we don't need to have another scene later where she's watching him swim and impressed by his shoulders again. Yes, Mac may have great shoulders, but we only need to see them one.
3) Figure out the point of every chapter. A chapter should take the reader somewhere--introduce a new question and help us to get to know a character or place better. If there is extraneous dialogue or description that doesn't have a purpose or lead somewhere (setting the mood or tone, setting up the dynamic between characters, setting up conflict... these are all places that the writing needs to lead--if this isn't where it's going, take it out.)
4) Find all instances of back-story and highlight it. Is it needed? Is it needed there? And is so much of it needed? Can you take three paragraphs of back story and condense it into one sentence? Can you sprinkle a few hints here and there in the dialogue?
5) Ask the question: Does this scene drive my story forward? If there are any places where the pacing slows (long explanations, long descriptions, long prosy thoughts) and try to cut them down.
6) Play with words. "Jenny heard Mac grunt when he picked up the hay bale." Instead say: "Mac grunted when he picked up the hay bale." You don't need to say "Jenny heard" We know she heard it since we are in her head. This seems nitpicky--but trust me--they add up.
Its all about tighter writing and tighter storytelling. It takes a lot of work, but it's worth it.
What other suggestions do you have for cutting down word count?