I'm not sure about this way being the quickest but it's certainly quieter than your alarm, hah.
The way I've accomplished lucid dreaming in the past is by resting flat on my back and keeping my hands either to my sides or crossed over my chest (that's just my way of protecting myself in my attempt). I close my eyes and pretty much wait for the sleep to come. Waiting keeps me aware, so when I begin to dream I can recognize it as such. It takes a bit of time, maybe 20 to 30 minutes before feeling that weightlessness, but it works for me. I believe practice will make the process quicken, though!
Also, a bit of advice in preparing for lucid dreams: I suggest that you create some barrier to protect yourself if you haven't already. I like to imagine a bubble around me, and crossing my hands over my chest equally serves as comfort. I think it's important to feel safe before making yourself vulnerable like that. I've had a poor experience because I didn't protect myself beforehand and the problem took time to fade, often times worsening just as I thought things were getting better. I'm not trying to be scary or anything, I just want other dreamers to be cautious. Be very protective of yourself!
Hopefully this is helpful!