How to: Social Media Career Cheats
Press Control + Shift + C then type testingcheats on and press enter. You can now get promotions with careers.promote socialmedia - you can also see all Career Cheats or visit a full list of Cheats in The Sims 4.
Social Media Career Levels 1-3
The initial ideal mood is Playful. Since the skill requirements for these first 3 levels are not very difficult, consider which branch you will take so that you can begin to raise the skills you'll need. This will smooth out the promotion process and make it a little less likely you're stalled on one level for a long time.
The Ideal Mood for this branch of Social Media is Focused. Your new daily task, Network with Journalists, is found on the computer. Given the need to get up to 10,000 Followers on social media, you should be working on this even on levels where it is not required. Just a post here and there will do. The more followers you get, the more you'll gain as they help you to market your profile. When you are away from home, use the Shout Out/Status Update from Venue ability that is found on your phone under the home tab. It gives more followers than the usual computer interactions, but does feature a cooldown.