@MyZelda9 Okay, first thing - Stop and take a breath. Then ditch the I'm not good enough attitude. Everyone started off as crap, just depends on what age that was. The stuff I used to post when I started with online BB Rp's or Chat rooms back on WinMX and Prodigy... Omg... It made the Free Section look like Shakespeare.
It does take time to get better but surprisingly it doesn't take as much effort as one would think. You just have to add a little more at a time. Don't try to go from what you are currently posting to 20 pages in one night. Look to add just one more line per post at a time. Easiest way to do that? Simple - pick one thing to focus on. Say your character is talking to someone and they ask directions.
Your character can go -
"Yeah, you head down the street three blocks and turn left. It's about half a mile down on the right." That could be your post but if you pick a single thing to add you expand your post. Let us pick hand gestures. -
"Yeah, you head down the street three blocks and turn left. It's about half a mile down on the right," he said as he lifted his arm and pointed down the street and then gestured around the corner.
See, just a little more. Over time, add more and more things. I have a list of things I try to touch on when I have a character responding to another. Eyes(Darting, looking this way or that, narrowing, so forth), hands (are they at my characters sides, held up, in my pockets, etc.), lips (Pursed, agape, slack jawed, blah, blah blah) - I just add in what is relevant.
Just start with the basics and work slowly. It won't take long before it becomes second nature and you are pumping out posts you never thought you could.
And never be afraid to join an Rp where you would be around people you want to be able to post like. Join it! You never know what you will pick up. ^_^