Once you’ve learned all the basic vocabulary in French, it can be tricky knowing what vocabulary to learn next.
A good way to identify the vocabulary that you still need to learn is by speaking aloud to yourself. For example, try speaking aloud in French for 5 minutes non-stop on a topic of interest or importance to you.
As you speak, pay attention to what you have trouble expressing in French. When you’ve finished, find out how to say the parts that you struggled with. You can check a dictionary or ask a francophone.
You can try this exercise frequently every day to identify the gaps in your vocabulary. You can change the amount of time you spend on it as you see fit, perhaps increasing it as you go along.
I like this exercise because it will guide you to learn the vocabulary you are likely to need in a real conversation.