Memorizing the meaning and knowing how to use a word in a sentence perfectly, requires more than one repetition depending upon how difficult the word is. You can have a grip over a word in a few repetitions if it is common but if it is uncommon then it's going to take more repetitions to have you ready to use it effectively and correctly. I also suggest you take the phrase "Quality over quantity" into consideration while learning English vocabulary, it means learn new words but not in much quantity because if you go for learning more words than it is probable that you will forget them quickly. Learn not more than ten words per day, and make a habit of revising so that the words retain longer in your memory.

Now what could possibly be a better way to memorize words, is a question which may have many different answers as it varies from person to person, so I'd like to suggest you to pay more attention to new words while reading because you, being an aspirant, have to tweak your reading skills so that you could improve your vocabulary while reading anything. So don't just read but also pay attention to new word that how it has been used in a sentence. Look at word and understand that how it has been used in a particular context. Last but not least, make a list of words which you find difficult while reading and look them up in a dictionary later and if you find making a hand-written list of words difficult then you can save them as bookmarks in your browser.