Serving very spinny serves makes it hard for your opponent to initiate the attack as he is forced to focus on returning your serve.  Here are some of the most popular serves.

Start with these videos demonstrating various serve and serve return techniques by Chinese players.

Forehand service : short and long under spin serves.  Note the point of contact (height) and movement of the racket as it follows through.

Forehand receive:
  drop shot, flick and topspin receive.  Note the off the bounce return for drop shots & flicks.  Note the first and second timing for topspin return and lowering your body.

Backhand service:

Backhand receive:

Forehand topspin:

Receive techniques: Returning short underspin and side spin serve on your forehand side.

How to make your serves more spinny.  Explanation of fine points.

Pendulum Serve

This is by far the most common serve you will encounter, because it allows to apply different spin with similarly looking technique and is most often played from server’s backhand corner into receiver’s backhand corner since most players don’t have sufficiently strong backhand to attack it.

Demonstration of pendulum serves like the ones by Ma Lin.

The left side spin serve by Ma Long
Ma Long training his serves.  Notice the many fake motions he makes before striking the ball and after.
Yet another demo of the short underspin server.

Serving sidespin pendulum serve explained in German (with subtitles) and how to play 3rd ball.  Very good explanation using animations.

Penholder grip – serving side-under spin and side-topspin serves

Reverse Pendulum Serve (a.k.a. inside out)

This serve used by Chinese player Zhang Jike and others is quite difficult to master but looks great.  See these videos on how it is done.
The Inside Out serve (right sidespin & backspin pendulum serve by Kranga)
Various inside out serves by Michael Maze
Inside out serves video showing the touch points on the paddle for generating 3 similar looking serves each with a different spin like those of Timo Boll. by Di Lan Go
Nice explanation of fine points of inside out serves like those of Zhang Jike. by Di Lan Go.

Another great demonstration by Russian player.

Ma Long’s Serves

Here is a video of how Ma Long makes the serves bounce twice or more times on the table in the forehand corner to throw off backhand dominant players like Zhank Jike or Dmitry Ovtcharov.

Miu Hirano’s serves

Miu Hirano a 17 year old Japanese player who beat all 3 top Chinese women players in Asian Championship has as top spin and under spin serve which tested even the best players return technique.  Here is the video teaching it.

Her serve is a variation of Jab server – you are jabbing the ball.  Here is an explanation of this variants of this serve by coach Ely Beraty.