Maybe you like to create characters on the fly, personality type them *cough*, or find a name and let them write themselves. There really is no one "right" way to create a character. But while variety is needed, what do you do when you have a sibling set with the same upbringing and home or
One of the most basic things you can do is give one a distinct something that the other doesn't have. This could be literally anything:
- facial feature
- catchphrase
- habit
- fear/struggle
- condition
- goal/motivation
- cute pet
- race/gender
- clothing style
- taste in music
This is not revolutionary by any means, nor does a single character need to have every one of these! A little goes a long way to making a character--especially a side character--stand out in a reader's mind.
On the flipside, there are some given things in life that people can't share without conflict. Like boyfriends or the last bite of cookie. Give multiple characters the same unshareable desire and watch their true colors come out.
Another option is to trace different means to the same end. In other words, explore how characters have different ways of reaching the same goal. Their motivation might be the same, but what are they going to do about it?
Or once again you could do the reverse of this. Characters who begin the same can take divergent paths. Maybe these are siblings with a similar past who lead vastly different lives. Showing different results from the same event (because it affected characters differently) can be very powerful.
In my mind, making similar characters unique comes down to reactions and interactions. This is where your plot and characters meld to make a story.
Any character tips to share?

