Flirting is supposed to be fun and so should it be, and it does not work if you intend to make fun of someone. To keep it light and fun remember to compliment him often. Smiling and laughing can also help lift the mood a little.
The best tip to be given here is to never target the specifics and always use generalized forms in your jibes and flirtatious comments. This will help you avoid unnecessary awkwardness and keep your comments in check.
Flirting can be used as a great tool but it is not advised to be a flirt all the time. Many people find flirting discomforting and would rather avoid being played by anyone. If you want to know how to flirt you should know when to stop flirting. Flirting if playfully done should be fun but it must never be offensive.
Overplaying your flirt hand is not recommended and it is best to get to know your partner better before taking it a step further.