When I read posts on how to create character profiles or character sheets they seem to preface it by acknowledging how much people hate doing them. Well, I guess I'm strange because I love them! Character sheets, oh how I love you. Let me count the ways:
Video Games: It's like building the perfect character in Sims. I played the video game Sims for years and I used to love creating every aspect of the character even mentally coming up with a backstory for the character as I played. I have a feeling that all you video game players out there will understand this one. Oh and everyone who played Sims remember coming up with elaborate death scenes...oh was that only me? Oh well.
Personality Quizzes are Fun: Growing up, I loved doing personality quizzes in magazines. At times I would try to guess how my answers affects the results of the quiz. Creating a character profile is a fun way to tweek things about a character and seeing how it affects their reactions.
I'm Forgetful: I have a full-time job outside of writing fiction. That means that sometimes I go weeks even months between character creation and actually writing the story. Additionally, I'm not the best at remembering facts about people I know in real life. So, when I have to stop writing for a few days I sometimes forget key facts about my characters. This means that these profiles serve as a convenient cheat sheet reminding me of key aspects about each character.
Surprise Characters: Sometimes doing a character sheet shows me the character already exists. This is more evident in writing a series. In book one of my current series, I created a very strong minor character. Then when I began world building for book three I did a character profile for one of my 'new' main characters and realized it has the same traits/background of the book one minor character. So I used that character. Hey ,it is obvious the character was trying to tell me I forgot them and messed up.
To create character my character profiles I use a template from Evernote. They seem to update this every year. To find the 2017 version go here (12 Creative Writing Templates for Planning Your Novel) or google 'Evernote character profile' and I'm sure you'll be able to find one of them.
This year I'm also making 3x5 Character Cards so that I can have a handheld physical cards for each character. I'm using those when I write at coffee shops or libraries and want to visual representation of my character.
To do this I printed and taped a inspirational photo of my character on a 3x5 index card. Then on the opposite side of the card I wrote the character's: name and nickname, family member's names, occupation, love interests, pet names, and any other quick relevant item I need to reference a lot.
There are a lot of other resources for character sheets and how to create them. When it comes to writing, I've discovered there is no one system. You have to use what works best for you.