Help me adjust my goals

Me and my partner are both planning to start small businesses, so decided that should learn seo to give us an edge and save some money.. But I thought if go a bit beyond the basics I could create a second income stream. I'm working in hospitality, so pretty fucked hours. How much do you think i can earn working 5-10 hours a week let's say 6 month from now when I manage to get to a decent level? I realize that this sub is probably spammed by noobs like me... But i really appreciate any advice or pointers. Thanks a lot!