Sort:  

you dont need to invest in steempower at first, even with comments you can earn your first bucks and then invest them ;) so just hard work

Sometimes the upvotes in your comments are based on luck or how much followers do you have and not based on the content of your comments. =/

even if sometimes you need to have luck and sometimes you are not gaining even cent, you can check successful people profiles and where they comments and try to do same , even if you still receive zero dont give up and continue to work :)

Thanks for the support mate :)