Dear Casiopea,
I use brackets (). I have not as of yet studied in depth the diagramming structure in sentencing so for now I use brackets. I do not outline and have my own way of outlining the points of the sentence using basic ad simple words in the first sentence and then use synonyms in all the other paragraphs. For now I use brackets. Will get back to you as soon as I understand the sentence diagram I understand a flow chart and mind mapping which is like sentence diagramming. pljames