#1 Remember l’ can precede either a masculine or feminine noun that begins with a vowel or “h”:
L’école – the school (f)
L’ami – the friend (m)
#2 with this/that you only use cet if it is a masculine noun that begins with a vowel or “h”:
cet home – this man
cet animal – this animal
#3 Remember that whether you use son or sa has to do with the gender of the thing, not the gender of the person owning the thing.
Sa pomme – his apple
Son oncle – her uncle
#4 Also remember that for mon, ton and son if the thing you own is a noun that begins with a vowel or “h”, you use mon, ton or son even if the thing is feminine (it’s like the an apple thing)
Mon agrafeuse - my stapler