How do I remember whether a Hindi noun is masculine or feminine?
Learn the gender with the noun, never separately, and use the endings as a rough guide: most nouns ending in आ are masculine and most ending in ई are feminine — with real exceptions.
There is no complete rule, and any site that promises one is selling
something. There are useful tendencies and a technique that works.
The tendencies
Nouns ending in आ are usually masculine: लड़का, कमरा,
पैसा.
Nouns ending in ई are usually feminine: लड़की, कुर्सी,
रोटी.
Most nouns ending in -ता, -आई or
-आवट are feminine.
And then पानी is masculine despite ending in ई, and आदमी is masculine too. The
tendencies get you perhaps seventy per cent of the way, which is useful and is
not a rule.
The technique that actually works
Never store a bare noun. Store a short phrase that carries the gender:
not किताब but यह किताब अच्छी है. The adjective ending encodes the
gender, so recalling the phrase recalls the gender, and you are practising the
agreement at the same time.
Why it matters more than it seems
Gender does not stop at the noun. It reaches the adjective and the verb, so
one wrong gender produces two or three audible errors in a single sentence.
Practise this with a teacher
Reading an answer is one thing; being corrected while you say it is
another. EkGuru tutors teach one to one from
$6
a lesson, and most offer a trial.