Uhh..I can't find the starmaker skills page tbhCan you tell where it is located?If you don't mind spoilers you can check out the walkthrough linked here
https://f95zone.to/threads/starmaker-story-v1-5c-arvus-games.218071/post-16586821
you get the second heart at 300 subs. This becomes easier after unlocking skills on the starmaker skills page (long press icons, they start from the top) - but it took a bit of time. Do other side quests to get more xp to get more stars. Make sure you focus on taking as many photos as you can. However make sure you unlock all wardrobe scenes before hitting the goal (go to the wardrobe upstairs first thing every Wed afternoon).
Also I recommend saving the weekend trips for much later (4 or 5 stars). Spend the money on Cameras and Campaigns intead.