I'm a Dutch student at university and I came across some major problems in one of my courses. During phonetics we have to be able to write the pronunciation symbols (IPA) of any word in English. When I'm making these exercises I find it very hard to distinguish the difference between the vowels /e/ and // e.g. in the words ten and hat.
Can anybody help me with this problem? Because when I have to "translate" the given word into phonetic symbols, I always doubt whether to use /e/ or //.

Thanks a lot already :)