Reddit mentions of Comedy Writing for Late-Night TV: How to Write Monologue Jokes, Desk Pieces, Sketches, Parodies, Audience Pieces, Remotes, and Other Short-Form Comedy

Joe Toplyn has a good book on writing packets for late night TV shows if that's what you're thinking about trying to get in to. I read the book last year and have since to forget everything it contained so I can't be much help, sorry.

Here's a link to the book anyway:

http://www.amazon.co.uk/Comedy-Writing-Late-Night-Monologue-Short-Form/dp/0615953891

• Improv classes. Especially in a school structure that teaches the concept of 'Game'
  
  
• Scott Dikkers (The Onion) How to Write Funny
  
  
• Upright Citizens Brigade Comedy Improvisation Manual
  
  
• Joe Toplyn's Comedy Writing for Late Night TV
  
  
  -----------------
  
  There's three in book form. Take them all and ingest them into your grey matter and develop your own.

Do you have a local improv theater in your town? Classes usually run about $100 for a few weeks, though sometimes they do one-off one day workshops. Taking a few levels of improv class will definitely help you. Though really if you can get through the first or second level and make friends to just practice as you go you'll get better.

If that's a bit too steep for you, consider looking at getting a book (not on improv, the benefit of improv classes is that it forces you to actually get up and do it and get critiqued). This book is on Late night writing, but a lot of the basic principals of humor are spelled out very well and the rest of the stuff could provide useful as well.

http://www.amazon.com/Comedy-Writing-Late-Night-Monologue-Short-Form/dp/0615953891/ref=sr_1_1?ie=UTF8&qid=1427736663&sr=8-1&keywords=Late+night+writing

There is a "Stand up comedy bible" that's a bit outdated. The first few chapters are okay though.

This book for late night writing also has some pretty decent bits of info.

Comedy Writing for Late-Night TV