First stab at TH:
http://www.hyperedsoftware.com/blog/entries/first-stab-th.html

SOH-TH:
https://www.fpcomplete.com/user/marcin/template-haskell-101
https://www.fpcomplete.com/user/marcin/quasiquotation-101

Tutorials:
https://github.com/leonidas/codeblog/blob/master/2011/2011-12-27-template-haskell.md
https://wiki.haskell.org/A_practical_Template_Haskell_Tutorial

UserGuide:
http://www.haskell.org/ghc/docs/latest/html/users_guide/template-haskell.html

Wiki:
http://www.haskell.org/haskellwiki/Template_Haskell
http://en.wikipedia.org/wiki/Template_Haskell

monadloc:
https://github.com/pepeiborra/monadloc
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/monadloc

2020
https://www.tweag.io/blog/2020-11-25-asterius-th/
https://jmtd.net/log/template_haskell/boilerplate/
https://jmtd.net/log/template_haskell/
2015
https://www.parsonsmatt.org/2015/11/15/template_haskell.html


Every time you want to write something in TH, you start with:

runQ [| ... |]

GHC will tell you how to write it. For example, if we wanted to write a splice that will produce 

\(x,_,_) -> x

$ ghci –fth
> :m +Language.Haskell.TH
> runQ [| \(x,_,_) -> x |]
LamE [TupP [VarP x_1,WildP,WildP]] (VarE x_1)

> :t it
it :: Exp

That’s it, no need to remember anything! Just ask GHC!