There's no replacement for experience, you have to build a complex application to know where React / InsertFavoriteFrameworkHere fails and where it excels. The best way I learned to gain this experience when you have none is to work for free / shitty pay, and struggle through the pains of being an inexperienced developer working for an inexperienced employer. Alternatively you can look for open source projects that you like, and contribute to them, growing your network and experience at the same time. I've always been a "yes" man, and it's served me well in life.