So I'm really thinking about making materials to sell on TPT. I make them for classroom use all the time and would really like to take it to the next level...however, (and this is where you come in!) I'm not sure the best way to go about starting. Is there anything helpful you learned along the way? Anything special to know about copyrights and such? Freebies vs. Not Freebies? I'd love any and all advice!