I generally ask this question in a huff of frustration. And, depending on my surroundings, some low volume swearing.
Textbooks are very kind to offer tables listing all the available conjugations. But sometimes people don't want to be shimmied at by a table. Sometimes people want flowcharts.
The pronouns you use frequently will probably find themselves etched onto your brain rather quickly. However, in lieu of frequency and brain malleability, I'll labour over some nonsense to help you remember which pronoun to sentence with.
[ANA]. Me. Singular. First person. Non gender specific.
If your name is Anna, this will be easy to remember.
If it's not, pretend it is. Problem solved.
[NAHNOO]. Us/we. Plural. First person. Non gender specific.
'Hey folks, what are you all up to?'
'Whom? Us? We? Why, nah-thing new. Nah-noo.'
[ANTA]. You. Singular. Second person. Masculine.
'Oi, hey Anthony!'
– radio silence –
'Ant! Ant, are you free for a date? Anta-r you free?'
[ANTI]. You. Singular. Second person. Feminine.
'Hi Priscilla, are you keen on a date with Ant?'
'What! Are you anti-dating?'
[HOOWA]. He. Singular. Third person. Masculine.
'Jeremy, who-are that person over there?'
'I think you mean who is that person.'
'Nope. I like saying hoowa.'
[HEEYA]. She. Singular. Third person. Feminine.
'He are the most beautiful woman I've ever seen'.
'Stanley, what are you on about? Firstly, it's a 'she', and you say she is.'
'I'll do what I want. Heeya the most beautiful woman I've ever seen.'
[ANTOOMA]. You. Dual. Second person. Masculine word, but non gender specific in use.
I have two friends called 'Ant'.
Sometimes I say 'Ant, Ant my buddies'. Or 'Ant-two, ma bros'.
[HOOMA]. Them. Dual. Third person. Masculine word, but non gender specific in use.
'Marceline, whom-are those people over there?'
'Those two people?'
'Yes, hoo-ma they?'
[ANTOOM]. You. Plural. Second person. Masculine word, but used to refer to all males, or a mix of males and females.
Ant, Ant and Ant (in unison): 'you have three friends called 'Ant'‽'
'Ant, um, it's easier to remember all my friend's names.' 'Ant-um. Ant-oom'.
[ANTOONNA]. You. Plural. Second person. Feminine.
'How many aunts do you have?'
'Three. And they're all called Una. So I address them together: Aunt-Una. Plural.'
[HOOM]. Them. Plural. Third person. Masculine word, but used to refer to all males, or a mix of males and females.
They are at McDonald's singing, 'm m m m Mac time'. 'Who?' 'Them.' 'Who?'
'Mmmm Mac time.'
Hoo-mmmm. Mac time.
[HOONNA]. Them. Plural. Third person. Feminine.
'There are three women waiting for you in the cupboard!'
'Which cupboard? What? Who? Narnia?!'