If it were me I'd write both the greek and the english words on an A4 piece of paper. I'd draw (or print out and stick on) a picture of a strawberry, then hang the poster up on my wall and look at it every night before bed. The act of creating the poster as well as revising it every night would mean it would be burnt into my brain pretty quickly. I do this with most words I struggle to remember.
That sounds like a very productive way to learn. Of course, it is time-consuming and I think with the many repetitions required by the course you'll learn the words without so much effort. At least that has been my experience with the courses I'm doing.
Btw....please be sure that poster says: "grape". ("strawberry" is "φράουλα") ;-)