it depends on specialty of it job , if its web development you should learn more of basics how http protocol works how requested and responses work, then you should choose if u would like more backend or front end , depending on specialty or you can do both(full stack) you could learn more about html/css and javascript basic with some frameworks, otherwise u can learn more about OOP and design patterns (solid, ioc ,....), version control like git , vsts, ... would be a plus, lastly read about some project management like agile methodology as scrum ...