Social media: in today’s society nearly everyone has all types of social media where many people post photos or thing that people could easily get inspiration from
Other artists: by looking at other artists work you can see what you like about them and interpret it into their own style
Everyday life: seeing people, nature and even animals can give an artist unsound what type of thing they like to draw or design
Friends and family: your peers opinion doesn’t entire matter but it good to get feedback on what you can improve and what they like about it
Hope this helps :)