Most learners forget new vocabulary because they study it once and then move on. Memory strengthens through repeated retrieval. If you want words to stay available when you need them, you have to revisit them before they disappear.
Use active recall instead of passive review
Looking at a translation and thinking, "I know that," is not enough. Cover the answer and try to produce the word first. That moment of effort is what trains memory.
Review words in short spaced sessions
Spaced repetition works because it brings a word back just as you are about to forget it. A few minutes today, tomorrow, and later in the week is more effective than one long review session.
Learn words inside phrases
Isolated vocabulary is harder to retrieve. A word attached to a phrase, situation, or image becomes easier to remember. Instead of learning "to eat" alone, learn "I want to eat" or "we are eating now."
Keep the list small enough to use
Ten well-learned words are more valuable than fifty half-remembered ones. Limit yourself to a manageable number and focus on words you are likely to encounter again soon.
Say and write new words
Using multiple channels helps memory. Say the word aloud, write it once or twice, and then place it in a sentence. The goal is not busywork. The goal is to give your brain more than one path back to the word.
If you want to memorize vocabulary faster, focus on retrieval, spacing, and context. Small sets, repeated often, will outperform large lists almost every time.