I want to design book covers.

Hi! I got my bachelor's in graphic design in may of 2025. And I work as a receptionist rn I want to switch to designing book covers but I don't think my portfolio is suited to get me jobs in that area. Would anyone be willing to give some loose guidelines or a checklist to put in a portfolio? I will be looking at YouTube for design challenge inspo but I'd also like to hear from people more experienced than me. Thanks in advance and please delete if not allowed!