I try to make sure my hands are either side of me when riding, you could try pointing at the nose and tail if you like. If they start moving around I know i'm not staying parallel. When I go toeside I bend my knees pushing them slightly out. Seems to work for me i'm no pro so yeah. I also found out that when I went -18 18 it made me ride more open so I reverted back to -15 15 which seemed to do the trick.