Do your homework. Research the districts you plan to apply to. Are there specific programs that they implement that you have been trained in? Is there a particular teaching philosophy that is adhered to that you also follow? These are things that can be mentioned in your letter of interest AND in your letter of recommendation.
Provide a list of traits and skills that you would like highlighted in your letter. Discuss this with your letter writer to make sure you are both on the same page.
Give your letter writers at least two weeks notice to write a letter for you.
Provide a deadline for your writers to have the letter done. Ask them if you can be of assistance in any way to write it.
Provide your letter writers with addressed/stamped envelopes to mail the letter to the proper location.
Keep them short and to the point. Include all important and necessary information with examples, but stick to one page.
Keep a copy of the letter and WSPA form readily available. This will help you be consistent when filling out the forms and answering questions during reference calls.
Include the "buzzwords" in education today if it reflects your MIT: differentiation, student centered assessment strategies, classroom management, culturally responsive teaching, etc.
Proofread your letter to make sure there are no typos or grammatical errors.