Honestly don't worry about the formatting too much. I used to get on anons for it until I saw many 4chan archives from 2003-5 that were filled with anons reddit spacing, using tumblr grammar before tumblr existed, and using lolspeak. In other words, anons have formatted and talked in a myriad of ways for many years and the collective beatings we give each other are more to just collectively beat each other than to actually maintain any culture. It's somewhat taboo for me to be explaining all this upfront, anons are generally supposed to learn through the aforementioned beatings, but I like this place and find it more constructive to explain on smaller boards.
That said, posts are generally considered more readable when formatted without a space inbetween paragraphs, opting instead to just hit enter and type new paragraphs on the immediate next line. Grammar doesn't matter much, but at least using capital letters at the start of a sentence and using periods is generally appreciated too.
/\ The paragraphs above follows readability formatting convention. I've noticed that sometimes spaces between large paragraphs when there are a lot of paragraphs are tolerated depending on the board too. Some boards will call this "reddit spacing." Notice how my first two paragraphs don't have a space between them but this one does. Below I will provide an example of what I personally consider to be true reddit spacing, this is actually kind of obnoxious in my view, but board culture too has embraced it in various points of its own history. In terms of vernacular, you will pick up what words mean and what normal words to replace with board culture synonyms overtime.
im writin dis 2 demonstrate teh most obnoxious form ov formattin
in da 2000s dis wuz wai MOAR common
ins't dis kind ov annoyin?
imagine readin it on CRT ( ◕▿◕ )
(Secretly though, I love old emoticons, and am totally fine with them, this board seems to be too sometimes.)