I had a very strange problem. In my slides for teaching LaTeX I wanted to tell people that they have to write ``test'' to get “test” (in correct quotes). But if you write ` in LaTeX, you get… a single quote sign! So I tried verbatim, \verb|`| and \texttt{`} – which all gives something that looks like a LaTeX quote sign.

After quite some frustration I found the following:

\`{} gives ` (grave accent)
\'{} curiously gives ´ (acute accent)

The straight quote is the hardest, after reading about many creative ways at stackexchange, I chose the easiest: Include package textcomp. Then

\textquotesingle gives ' (single straight quote)

What a mess!