DB autogrowth issue

I have a database that will growth in 1 month time the autogrowth was set to 500MB but as I monitored it, the consumption is 1GB+ per day. Should I wait for it to auto grow or is it better to set the initial size to much bigger size? Or set the auto growth to much higher size? Another thing is the timing of expanding the size, is it ok to do it online while there is a production will it have a minimal impact to our production or should I schedule a downtime? Thanks for the response.