If I was teaching a TV class, I would write in big fat letters on the board:
C H A R A C T E R S
Your show NEEDS good characters. Great characters. Characters the audience is going to want to follow for dozens of hours. Characters where, when the only people reading your script are an overworked intern in a management company, goes "wow, I wanna know what happens next to them!" Characters that surprise the reader, surprise yourself. Characters where you think you could write 6-7 seasons about them and not have it feel repetitive.
With your script all you have is your words. The script could be turned into the most amazing project ever with the right direction, set design, editing, etc. but unless the words are leaping off the page, it won't matter before it even gets greenlit.
A big issue a lot of beginning screenwriters run into is engaging the reader. The best way I can think of is, you're telling a campfire story. It's not a novel, but it's not a bullet point list of descriptions either. Make the scenes pop out in the reader's mind. Throw in humor (if tonally appropriate) to catch the reader's attention. There's a great example of this in the Lethal Weapon script (Shane Black was infamous for this):
"EXT. POSH BEVERLY HILLS HOME – TWILIGHT
The kind of house that I'll buy if this movie is a huge hit. Chrome. Glass. Carved wood. Plus an outdoor solarium: A glass structure, like a greenhouse only there's a big swimming pool inside. This is a really great place to have sex."
Also this from another film:
"Remember Jimmy's friend, Henry, who we met briefly near the opening of the film? Of course you do, you're a highly-paid reader or development person."
That's how I would do an intro to TV writing, anyway.