Many people tell me that they are learning vocabularies but they are finding it extremely difficult to keep those words in their memory for a long time. I can feel your struggle, trust me. I had this same problem.
Let me tell you why this is happening. Suppose we’re learning 30 new words per day. Yesterday we learnt 30 words. Today we again start learning new words without recapping the 30 words we learnt yesterday. Thus, we forget most of the words we have learnt previously. That’s the root of the problem. Our strategy for today should be to first revise the 30 words we learnt yesterday and then start studying the new 30 words. Thus, you can understand your workload will be increasing day by day. A week from today, we have to revise 210 words we learnt throughout the week and then we can think about the new words. Another thing you can do is to stop learning any new words for 1 or 2 days and revise the previously learnt words for that time. This can work too.
Also, try to use these words in your write-ups. That’s another way of keeping these words in your mind. The more you use these in your day-to-day life, the higher your chance will be to keep it in your store. Try to write at least 4-5 write-ups every week and use the vocabularies there. It will boost your confidence too.