<p>I understand that you must have a good bond between the professor and preferably some work experience under the professor when asking for recommendation letters.</p>
<p>However, would it be a good idea to ask for any comments on your SOP while also asking them to write you a rec. letter?</p>
<p>I thought this way, the professor would know even more about you and therefore write a better rec. letter with ease.</p>
<p>When students ask me to write a letter, I ask for a CV, and, if they are comfortable with this request, adding a copy of one of their SOPs. That way I can “spin” my recommendation in a way that supports their SOP.</p>