tell your friend study more like me, than he will know how to read her girl (girls) even from her (their) facial expression to know the best time to proposed.

no need to be too nervous follow this simple procedures,

1) kneel down with a rose in hand
2) buy a big diamond ring at least 1 carat (the bigger the better chance)
3) say this three words " I Love You"
4) followed by "Will you marry me?"