Unfortunately, physicists and mathematicians keep using Greek letters in their formulas, so we just have to learn them.

A helpful way to remember is to learn a bit of their history/pronunciation: Section "Historical correspondence between Latin and Greek".

To learn the greek letters if you have a base latin alphabet, you must learn the sound of each letter, and which Latin letters they correspond to.

Symbols that look like Greek letters but are not Greek letters:

nabla symbol

Is Ciro Santilli crazy (he is, but for this point specifically), or do many/most Greek letters represent the mouth position used in the pronunciation of the letter?

Gamma ( $Γ$ , $γ$ , C, G)

1 0

It is fun to see that C and G have been confused since antiquity:

the modern sound is G
in terms of modern letters, both C and G split from gamma

Epsilon (letter, $E$ , $ϵ$ , $ε$ , E)

0 0

Confusingly, in LaTeX:

\varepsilon rendered $ε$ , is the default modern Greek glyph
\epsilon rendered $ϵ$ is the lunate variant

Zeta (letter, $Z$ , $ζ$ , Z)

0 0

Lower case looks like the mouth shape when you say Z, with mouth open, and you can even see the little tongue going down. Beauty.

Eta (letter, $H$ , $η$ , H)

0 0

Lowercase looks like a lowercase letter N for some reason.

Nu (letter, $N$ , $ν$ , N)

0 0

Why would physicists use a letter such that:

the upper case version looks exactly like an upper case N. At least that is the correct pronunciation/name/historical successor of $ν$ .
the lower case version looks exactly like a lower case V

Why? Why?????????

Rho ( $P$ , $ρ$ , R)

0 0

This one is a little confusing: the upper case looks exactly like a letter P, but as the name suggests, it actually corresponds to the letter R. The letter P corresponds to pi instead.

Two lower case variants... both used in mathematical notation, and for some reason, in LaTeX \varphi is the one that actually looks like the default standard modern lowercase phi, while \phi is the weird one. I love life.