Trying to improve on sketching

Hi I am trying to improve on my quick sketching and rendering skills. I am looking for some input into my work. I am trying to get it to be more in the round but some reason I still feel it doesn’t stand out enough. Any input would be great I am really trying to improve this skill. Oh and any suggestion on subject matter. I seem to get into a bit of a rut with fashion and product a bit. Thanks!