How to flirt with girls

Ok this is my first tutorial. Well the purpose I give this tut is because most of the guy out there kinda forever alone because they don't know how to flirt. I may not be very hot guy in school, but I do know many girls and vice versa.

1. Be friendly. Girls like to socialize and they are friendly too. I don't see a harm in being friendly to girls.
2. Be a humorous person. I've asked many girls about their taste and they prefer a man with good sense of humor over a hot boy.  Of course they will have a crush on them but they will fall in love to guys with sense of humor. Remember crush only will last for 4 months (based on research, you can google it) and anything beyond that is called love.
3. Don't talk about their weight. EVER. Girls kinda paranoid when it comes to weight (sometimes not). That's girls logic 
4. Smile always. Don't be a grumpy drill sergeant. Smiling prove to be useful in flirting with girls. Remember, girls first impression is fucking important.