I'm going to bold the errors I see and explain each one.
|Person 1|Flower walked up to the young horse,
use to her. After all,
she was going to be his
That comma is out of place. Your sentence tense looks weird with those words as well. It should be "the young horse that was use to her" IF that's where you were going with the sentence. It doesn't even make sense. Jay is, I'm assuming, the horse. What do you mean by "use to her?" Do you mean the young horse that WASN'T use to her? Also, the spacing is awkward. The third, fourth, and fifth responses are spaced properly.
|Person 2| Jay eyed the girl he
saw suspiciously. Could
he trust her? He had no
My only concern with this one is the spacing. An alternative way to write your beginning sentence might be: "Jay eyed the girl in front of him wearily. She was suspicious..." or "Jay suspiciously eyed the girl in front of him..." It's not too bad, though.
|Person 1|Flower reached out to pet his side. Off her sheet she read that he was called Jay. She supposed it must be because of the mark on his flank, it looked a bit like a flying bird.
The first part of that sentence is missing a punctuation. Try something like: "Off her sheet, she read..." or "She read off of her sheet that..." The next sentence is punctuated oddly and worded poorly. Something like this would be better: "She supposed he was named Jay because of the mark on his flank; it looked a bit like a flying bird." This might work too: "She supposed it was because of the mark on his flank. It reminded Flower of a flying bird."
|Person 2| Jay tensed, then relaxed into her hand. It felt good.
Word choice. Something like nice, relaxing, calming, anything would be better. Could also used more explaining. Perhaps show that he trusts her because of how gentle her touch is. Explain how the touch feels like to him.
|Person 3| John waved at Flower as he passed.
Who is this random person three? Why are they popping up in the middle of an rp between person one and person two? In MOST roleplay orders, you want to give everyone one response per round. Doesn't matter who starts it, but something like this makes sense: Person 1, Person 2, Person 3, repeat. Or Person 2, Person 3, Person 1, repeat. Not Person 1, Person 2, Person 1, Person 2, and suddenly Person 3.
The most common "error" I guess you can call it is that these entries lack a lot of showing. You're telling the story, yes, but you're not really getting deep into the character. You can say they were scared of the monster the monster. That's a nice way of telling. OR you can SHOW what their fear is:
The students' eyes widened at the sound of the roar. Slow, heavy thuds were coming from the left gymnasium entrance. Most of their hearts felt as if they were beating out of their chest. The thuds stopped at the door. One person let out a breath, but before anyone was calm, the door was knocked off of its hinges. Several screams broke out in the room as several students shoved their way past each other, scrambling for the right side of the room.
You also don't really write a lot, but for a beginner at writing, you're not doing bad at all. As you get more into roleplaying, you'll tend to write a larger response that will look more like a story that's not just one sentence per response. The best way to write more is to think like your character. Become them for the moment; really capture their actions and words.
Okay. I just made that up to see what three people might randomly do. Person three is somebody who was meant to be there, couldn't get on, and so people one and two continued without them, and then person three joined back in. The people are meant to be newbies, capturing a starting scene they might do before they can add action. Thanks!
BTW I forgot to mention
Smut in roleplays does count against you and will be deleted. Idk why I forgot to mention it while bumping but yeah that's all that's new. Additionally I think I forgot to cover script roleplays better so I might do a new section for that too, unless anyone else wants to talk about it and post their own thoughts here. :)