Asking for recommendations?

I’m a senior nursing student and I’m starting my job search. However, so many new grad positions that I want all need at least 2 references or letters of recommendations. Since all of my nursing classes have been online and I tend to be a shy and quiet student, how do I ask my professors for recommendations. I have had 2 clinical instructors but they both have always told me I have potential but I just need to “talk” more and stop being so “quiet”. However, that is me. Being quiet is who I am. I still passed all my clinicals and did just fine with patient interactions but I’m scared to ask them for a reference. I feel like they don’t really know me well. 
 

Any tips or suggestions on how to format the email to write them asking for a reference? What should I include in the email, how should I ask them? Right now I don’t have any specific jobs that I’m applying for. I’m just trying to get some references as I continue on throughout my nursing journey.