I'm not sure where else to put something like this. If this is in the wrong place then I apologize.
AE is a good game but to truly enjoy everything it has to offer you will have to put yourself in the shoes of your character. That is my first tip: if you are a roleplayer then you are an actor playing out a character-- but you are not your character.
If a letter isn't addressed to you then it wasn't sent to you, and your character has no knowledge of it ever being sent, even though you, the person behind the computer, have read it fully. Whatever the rules may be, the most important consequence of this is that it is disrespectful to other people who are also roleplaying. Show style, be a lady or a gentleman and respect the roleplay of others if you want your roleplay to be respected also.
Don't be afraid to say too much because generally more is better, even if you don't speak english well that's okay. No one is going to judge you on your knowledge of english because most people in the world probably only speak 1 language anyway. If you can hold a conversation, in any measure, in a language you were not born with then that is an accomplishment few others can claim.
In any case detail is good and if people didn't want to read your roleplay then they wouldn't have clicked on the thread in the first place. What I find to really give style to my roleplay is to be descriptive about things that really don't matter. Like if your character is going to say something then he might get up from the chair, or pound a fist on the wall, or walk towards the fire and stare into it. These small details show the emotion of your character in your words, otherwise your roleplay is just a bunch of words with no empathy that the reader can leech from.
To make your character different than other characters then you might want to give that character some habits that you can write about in your roleplay. Maybe your character bites their lip when they are nervous (this is commonly called a "tell" ), or gets angry easily (think: berserker), or has a weakness for his toothless servants (remember: no toothpaste), or anything else you can think of. Remember that you are not just roleplaying inside of a person but also inside of a world that other characters are also part of.
Roleplay can also be a learning experience because you can learn about things you did not know anything about previously. Like blacksmithing, or tailoring, or architecture, or anything else you want to write about but did not know anything about before you wanted to write about it. There is a lot of information on the internet that you can use to make your roleplay more descriptive and also learn something new in the process.
I will reply as I think of new tips, and I encourage others to do so also.
Please stay on topic. Thanks, and you're welcome.