Mistakes Russian speakers make
Russian has no articles, no auxiliary "to be" in the present tense, and forms questions by intonation. Russian speakers often translate too literally and drop English helper words.
Pick one to practise
Dropping "am / is / are" in present
Russian doesn't use "to be" (быть) in the present tense — it's implied. English requires "am/is/are" explicitly in present-tense statements.
Dropping articles
Russian has no articles. English requires "a/an" for first mention and "the" for known specific things.
Question without "do / does / did"
Russian uses word order or intonation for questions. English needs "do/does/did" + base verb in most question forms.
Present simple vs present continuous
Russian distinguishes aspect with verb pairs (perfective / imperfective), not with separate tense forms. English uses present continuous (am/is/are + -ing) for actions happening at the moment of speaking.