There could be number of techniques to remember a "Word"
One way is, when you learn a new word, try using it in a sentence. For example when you purchase any gadget, how do you remember its various functions? and the answer is by "Using", so similarly, use a word you learnt. For example: Abstruse means "Difficult to understand"
Sentence: "She gave an abstruse explanation of the problem at hand"
or there is another way in addition to the above, this needs little more practice, try creating a memory link for a word, we take the same word as our example, Abstruse means "Difficult to understand"
Memory Link: Truth is always difficult to understand"
Usage: "Abstruse argument"
"She gave an abstruse explanation of the problem at hand"
you see its easy to remember when you relate things. Cheers;)))