Supposedly, it is traditionally done with the the left knee on the ground and the right knee up. All in all, though, there are are probably more important things to worry about when proposing and I think that your significant other probably won't mind with the whole importance and excitement of the event.
Your left knee.
get on your knee.
He knelt on one knee to propose to her. He tried to propose a compromise, but they wanted nothing to do with it.
On one knee.
The old-fashioned way is getting down on one knee.
I'm not too sure to be honest
While she is staring at the ring you just offered her, she will not notice which knee you got down on. It doesn't matter.
You get down on one knee, present a ring and say, "Will you marry me?"
Proposing is a way of letting a girl know you want to spend your life with her. Do something unique for a proposal! Or, try doing it the "traditional way", on a date, bend down on one knee, and propose. Make sure you want to, it's a HUGE decision. <3 <3 <3
Generally when he gets down on one knee and pulls out a diamond ring....
Trip on some steps and let your knee cap hit the steps.
To propose a girl simply go to her and tell her that you like her. Tell her why you feel so and why you want to get committed. She will think about it and will tell you what she feels about it.