Okay, so I've been kind of out of this habit for a couple of weeks now, so I'm trying to get back into it once more. Hopefully it will be beneficial to myself or perhaps someone else, but here goes: the history. This is usually written last, and often rightly so, but I would consider it the second most important of the three core items in the character sheet, bested finally by the personality section that I'll be doing next.
I will be mostly attempting to dispel some notions about the history section that I see often but don't consider to be the most valuable approach to it - primarily length and density. I am going to be a little repetitive here, but it certainly is worth repeating and reiterating: quality over quantity. Unless you've really got my attention with a killer character concept, you're a good friend of mine (not because only then could I consider your writing worthwhile, but simply because it is an immediate prompt of personal interest), or (hopefully not) I'm worried there will be errors hidden in it, my immediate reaction to seeing a very long history is to simply go do something else. Play a game, watch a movie, doesn't matter - I'm not really interested. A character's history section in their sheet should not be a biographical masterpiece covering everything from the romance of their parents down to the first crush they had in the first grade. Simply because it is a part of the character's history that you as the writer knows does not necessarily mean that it's information you need your reader to know.
Instead of including every minute detail you may call upon in the roleplay as you act out your character, simply explain it on a need-to-know basis, and use it to strengthen your roleplay and the reader's understanding of the character as it becomes important. How do you know if things are important? My suggestion would be to ask yourself what the information affects. First and absolute foremost, does it affect their personality? Returning to the example of a crush in the first grade, on its own it would be an irrelevant detail, but perhaps that same crush played a bigger role in the person's life beyond just that. Returned in their later life? Some childhood trauma that occurred alongside the original feelings in the first grade may be unearthed on the return of the character in question. If this person simply vanishes from their life and the character moves on, then bringing it up served no purpose. Make sense? Personality is the most important, but if it affects the character's appearance (which often ties with personality, right?) in a large enough way or it affects their current location or state of being, then it will also probably be worth mentioning in moderation with its importance.
Now, it's possible you've gone through all this and checked all the boxes, but there is another very crucial thing to be careful about as well, and that's making your history too dense . This is returning more to the creation of the actual character, not just your write-up of them for the reader, and can be just as frustrating to sift through by the reader as the aforementioned problem. Once again, this returns to a matter of length ultimately, but on a larger scale it reflects the author's inability to be concise in the conceptual stages of your character. Let me get a little more specific in a moment, but first let me emphasize one thing I consider very important: we are writing roleplay here, not fanfiction. In the latter, writing a core hero of the story is something is essential; in a roleplay, your job is not to dominate the spotlight, but to essentially craft real characters in whatever universe you're immersing yourself into, that would be likely to exist and could coexist to some degree with other characters. There is a place for the hero that saves the day or the arch-villain that threatens the world, but there is a reason that those roles are usually taken with some sort of planning and often by members of the staff or officer board in the community. If you think that fulfilling roleplay comes from only playing the true hero of the story (which is often just escapism, as mentioned before) then I would suggest that you are missing a very important note of healthy roleplay, and it is both a crutch for your writing and a degrading aspect of the roleplay for those around you.
Okay, so back on track. In its simplest concept, the notion is that you don't need your character to have life-changing events occur to him ever year. Unlike a main character often has, your creation can experience life in a much more, dare I suggest, normal fashion. Since you do want the character to have some sense of direction and depth, you will indeed have large events in his or her life that shape the way the character plays out. These events, though, should have some sense of balance to their life, rising and falling in actions, but most frequently residing in a trough period where little is happening except perhaps a slow molding of character; that's just how it works out, usually. In a person's thirty year life, it's highly likely that only a handful of things happened that truly shaped the course of their life in a lasting way. I'm not talking about things like going to a university and meeting a number of people or getting fired from a job and being unemployed for a couple of months - while those may be big things at the time, they are not really lifelong.
The thing I'm getting at is watching your village be burned to the ground in front of your eyes, meeting your spouse or lifelong friend that redirects your hearts and longings, or fighting with that important person in a conflict that was never resolved, leaving your character hurt and bitter inside in a way they were not before. Events that, in a moment, restructured and redirected your character in a profound way. If you are telling the story of a swordsman and you detail every fight he had from the bandits on the side of the road to with his best friend, then the reader will quickly be lost in all the facts of your character's history that they no longer will hold weight. The easiest way for your reader to lose their understanding or even interest in the events at hand is to bombard them with information about your character, whether that means being too detailed or being too dense, your reader very likely will not care. Even if your character perhaps move around a lot as a child (parents in the military?) you likely do not need to detail every new circumstance, only the most important ones, if that. Touch in the main point, which is how it affected them in the long run as they were subject to it over an extended period of time, but you don't need to detail each different incident.
One last thing, though, before I finish up. There is a temptation when attempting to get a certain amount of length to a history to put roleplay inside the history itself - those little snippets when all of a sudden you were reading how your character reacted in a specific conversation, including dialogue and descriptions. It adds very little! Given everything I've ranted about so far, acknowledging and disapproving seems hardly necessary, but I will say that there is a place for that, actually. If you are truly in love with the character you are writing, create a condensed version for your typical reader who is hoping to get a basic summary and understanding of your character. When that's finished then you can set out making a longer version for your own pleasure. If you want to share, it post it in your community's writing section - they almost always have one. If your reader really does enjoy your writing or your character and wishes to know more, then they can opt-in to the challenge of seeing a very in-depth writing of the whole thing from start to finish.
It seems ironic that many sites would have a minimum number of words/lines/paragraphs/characters for a history section when most often it seems that people should be capped in how much they're allowed to put down. Ever written a précis? It's "a concise summary of essential points, statements, or facts." Take your 1,000 word history and write it in 250 words. 100 words. 25 words. It's challenging, to say the least, but doable, and it's the model of the character sheet. Make it look nice - make it enjoyable to read, but don't waste your reader's time.
"Therefore, since brevity is the soul of wit,
And tediousness the limbs and outward flourishes,
I will be brief: your noble son is mad"
