The letter Ё looks exactly like the letter Е but with two dots at the top. It is one of the least used letters in the Russian alphabet.
The tricky part is that Russians are quite lazy when it comes to putting two dots at the top of Ё, so in writing it is often indistinguishable from Е.
When it follows a consonant, the consonant becomes soft.
Within a word, the letter Ё is always the one that's accentuated.
Practice in syllables
Words with this letter
Д at the end sounds like Т.
Practice with a worksheet
Practice the hand-written Russian letter Ё, as well as the syllables and words listed above, with this worksheet: download the worksheet.