>>60858
4. Background
Before you delve too deeply into the mental aspects of a character, you should write a background. What kinds of things happened to him, what kinds of things has he done? These can be big things, like being beaten as a child, or small things, like buying half-a-pound of Havarti cheese every week. And all of these seek to flesh out the personality of the character, even if the background is never explicitly stated. Being beaten might make the character more gentle, kind, or it might make them more angry, hate-filled. Buying the Havarti might be because he is Danish, and was raised on Havarti, or it might just be that he likes the sweet taste. Now that's all black-and-white, and of course there's tons of grey area to travel through with it. Background includes everything that has happened before you start playing it. What job or jobs did he have? What car, if any, does he drive? Of course, these are simple examples, but details in the personality can come out of things like this. And this can, and should, make sweeping changes about the character, depending on what happens. He might have been in the War of 1812 and now hates the Brits with the same fervor his father, a Whig, did. He might have worked for years in a dead-end job before deciding to just move to Thailand for that boipussy. Because in the RP sense, you're only playing the character after the background, surprisingly. But that's not a steady rule, and there's no one saying you can't do flashbacks or origin stories.
But remember one thing: not everything you do affects who you are. If I have a slice of toast in the morning rather than cereal, that could just be because I was feeling too lazy to make cereal, not that I'm paranoid and have a complex about the milk being a week-old, and me thinking it would be spoiled.
5. Mental traits
You've gotten the background down, so what does it all mean? Mental traits include specifics about them, like the way they speak, the mannerisms, their tastes. This is also known as a personality. A lot of people have one, and I recommend you spend some time on making one. A good personality can make all the difference in the world, as it affects someone so completely and makes them 'someone.' Even the town bicycle has hopes and dreams.
What in their background made big changes to them? Like with how a childhood of beatings might lead to a bitter and angry person, or a bad car crash might lead to a fear of automobiles. Their upbringing would change their opinions on things, make them think differently. If they grew up with all their needs satisfied, they might be spoiled. If they were poor, they might be grateful for everything they get. Of course stereotypes can be subverted, etc..
Make a character with wants, wishes, dreams. Make one with fears, likes, and dislikes. But the key thing is to keep it realistic. Don't fucking make a Mary Sue. You can have a good back story, fleshed-out character, and interesting personality even without tragedies in their past. Run it through that Mary Sue limitus test or whatever if you really need to.
6. Refine
You're never finished making a character. Thing that happen later in their life, after the RP starting point, can make differences in later ones. They could move somewhere and begin to learn the customs of that place, causing changes to vocabulary and mannerisms.
But the most important part is: have fucking fun. This whole multi-paragraph essay is pretentious and autistic, so ignore it if you want. And the whole thing can be done in reverse, or in any order you see fit. This is just generally what I do, and hence why I've only got two characters. Because of this autism.