This post is inspired by a short story written by one of my critique partners. You know who you are :)
From time to time I've read articles about making men sound like men and women sound like women. Below are some generalizations to get you started if your alpha hero is sounding like Great Aunt Myrtle or if your sexy heroine reminds you of Joe Jock.
Men use a lot of articles to describe items. He picked up the ax to inspect it before chopping the wood. Women tend to personalize items. She tossed her hair dryer into his suitcase.
Men and women notice different things. In a waiting room, a man is more apt to notice the doors and windows, the seating arrangements - the architectural elements. Women will notice wall color, upholstery, accessories, scents. Women are more likely to notice other people in the room.
In conversation, the goal of men is to impart and/or gather information. A woman's goal is to build a bridge to the other person to build a relationship.
Men want the bottom line. And I mean that in the nicest way - LOL. Like Sgt. Joe Friday on Dragnet, for most men it's "just the facts." Women want to tell you the story. Women use more words than men to say the same basic thing.
Men love gadgets. Women love shoes.
Men think about sex much more than women do.
Again, these observations are not set in stone and none of them may apply to the people in your real life. Or even to any of your characters. But you can use them to nudge those stubborn characters in the right direction for your story if they're getting out of line.