I'm looking for good links to articles written about letters of recommendation. I'd like tips about how to "package" the request to the recommenders.

Additionally, in my current job of 3+ years (airline pilot), I don't have a direct supervisor. Instead, I work with new and different people everyday. With that said, I'm having trouble finding potential recommenders. In addition to one person that I luckily have worked with for quite a while, who else can I ask? Is it appropriate to ask an old college student-group adviser who worked with me for 3 years? I'm concerned, because he worked with me about 4 years ago, but he also knows my work very well.

Thanks for your help.