Review, reuse, repeat.
Reusing and repeating the same idea in different situations and contexts will help you make it your own in a way that you will be able to use it in your own situations and real-life contexts. Instead of spending time trying to memorize words and phrases, spend the time playing with different ways to say something or use a word.
Commonly, when we first start learning a language, we start by memorizing vocabulary and basic phrases. Of course there is an element of memorization when it comes to vocabulary, and memorizing certain phrases can be useful if you are only traveling. But the issue becomes that you are only memorizing a sequence of sounds, which makes it incredibly difficult to actually remember, much less use. As soon as you can understand the parts of the phrase, why they exist and for what purpose they serve, you move into the realm of learning and mastery. Then, you can take a basic concept and adapt it to the situation in which you find yourself. This becomes especially important in French as the endings will change depending on of course not just the tense, but also the subject of the verb. If you memorize a phrase where the subject is “I”, you won’t be able to use it if you want the subject to be “you” or “they.”