I just do the very best I can. My seam lines must line up exactly and points touch where they should and not ever chopped off; to accomplish this, I have to be extra careful and completely focused because I (a) have no sense of direction and (b) detest seam ripping and (c) never give up or discard any pieces. Seam allowances are what tend to give me problems; sometimes I press to one side and sometimes I press open to reduce bulk, but I usually end up with some seam allowance confusion, areas where a lot of seams meet and they don't want to cooperate.