Hey, sorry that you've been having rotten luck with role plays, but when you say people can write books etc.
It isn't like that, if you apply to a roleplay that is in the casual/advanced level they expect good Grammar and spelling as well as detailed accounts because the better it is the better the mental picture is formed in your mind, hence making the roleplay successful.
You don't need to be good at Enlgish for that, it's merely putting the effort in, for instance if you can't be bothered to simply capitalise your I's then you probably won't get in because they will think that your not capable of sophisticated grammar and general English.