How to propose a girl?

Simply buy a ring, and while u are talking, get down on one knee, think of some true words of love, then say, "(her name),will u marry me?

OMG! No way is it "simply buy a ring and yada yada" remember this is going to drastically change yours and your partners life! Make it special and memorable, think about where you will do it:
-where you first met
-where you had your first date
-somewhere she's always wanted to go
-somewhere that means something to you both
Then think about how you'll do it
-get down on one knee
-do something creative (like in spiderman he puts the ring in a champagne bottle)
-take a look at some on YouTube they have a kajillion videos of people proposing in cute ways
DO NOT ACT LIKE ITS NO BIG DEAL! Make it so special that she'll scream "yes!"
Good luck! <3

Use your heart and imagination.You know her best...what she likes etc...you could implement what she likes in that marriage proposal.