(This post is based on personal experience. Take away from it whatever you can.)
OMG! The same-gender characters have to talk to each other! How the heck am I going to distinguish one from the other?
I have trouble with that in my novel. My MC is a guy, his best friend is an old guy, his neighborhood enemy is a guy, he has an older brother, he has lots of guy friends and they all have a drink together in the village they live in!
I have to distinguish them without having to say,
"How are you?" asked Belome (my MC).
"I'm fine," answered Velodis (his best friend).
"Me, too!" said Iyar (his drinking friend).
"It's a good day today," remarked Belome looking up at the sky.
"Sure is," said Iyar.
"Great day," nodded Velodis.
SOUNDS LIKE a children's book.
How do I make it not sound like a children's book?
Of course their conversation is just an example and they surely do say much more interesting things, but it's HOW they say it that will distinguish them and what they do with themselves or think to themselves while they say it or after they say it.
My little trick here is "If you can't distinguish by speech, use body language."
Body language can be pretty powerful and it can show the personality of the character without saying it outright.
Belome is a friendly guy but he's a bit of a coward and not too outgoing. He might, look down at his sandals, or look around at the people around him because he's a little self-conscious, he might notice things that other people might not notice.
Velodis is an old grump, a philosophy man, an old farmer, not much sense of humor, he has grumpy days almost everyday.
Iyar owns a beer making business, he's outgoing, he's got a bit of village-country slurr, he's a bit touchy (like he'll talk to you and put his arm around your shoulders or something like that), and he's very proud of his beers and tells people about it whatever chance he gets.
So, that old children's book sequence will turn into something like this:
He found the old man near Iyar's, pulling his tangled beard and deep in thought. Iyar was shoving his beer under the noses of his customers who seemed less eager to buy it than he was to sell it.
"Oy, Velodis. How are you?" asked Belome, the old man was mumbling grumbling but he looked up at Belome's voice.
"I'm fine," he grunted and turned to walk away when Iyar came up behind him, pouncing onto his shoulders.
"Me, too!" he laughed as Velodis shoved him off. Iyar's cheeks were already flushed.
Did he already drink? Belome frowned. Sometimes he couldn't tell when his Brewer friend wasn't drunk.
"It's a good day today," Belome tried to bring the old man out of his grump. "Didn't you once say this year will be a ripe autumn? Is your old apple tree ready for harvest?"
"Sure is. Great day for a little drink, eh? How 'bout it, old man? Eh?"
"Already harvested. And great day," Velodis started to walk away. Belome sighed. Once you rubbed the old man the wrong way it was hard to get him back. He hurried to catch up, leaving Iyar to tend to more customers.
I hope you can see it, the difference. Belome trying to keep things happy, Velodis in his grump, Iyar just messed up and thinking about drinking.
They are all the same gender but they are distinguished. Well, I think so.
Let me tell you, it's so hard when several village guys and girls are all shouting out their opinions because I have to try to at least hint at their ages. Description does the magic here, really.
Description IS the magic :)