Not everyone has a gift for writing. Just like not everyone has a gift for cooking, or functioning as a productive member of society. It's okay if you don't know how to write. It's also okay to be earnest and try your hardest. But once you've done a couple of workshops and graduated college, your dearth of skill should be properly acknowledged and you should stop writing.
Now, I don't mean stop writing all together. I do mean stop blogging. If you have no gift - let it lie. And, at the very least, run a spell check over your post before you stick it up there for the whole world to see.