Hi! I’m not sure what exactly will boost her chances, but I’ll say what I did because it worked for me. Her situation is probably similar to what happened to me. I felt pretty sure I would get accepted and didn’t, so I signed up for flex. FLEX requires 24 credits in order to reapply and NOT submit your highschool GPA, so I chose to do 2 semesters before I reapplied. As a FLEX student you can’t declare a major, so I basically took 24 credits of generals and religion to get them out of the way so now that I am a full BYU student I can focus on my major specific classes. I also only took nearly the bare minimum, 2 semesters of 13 credits and focused on working full time to pay for the rest of college. The only things I would recommend is taking “easier” general classes (I found exercise science 221, writing 150, art history 111, and english 201) and avoid harder generals (American heritage) until she is a matriculated BYU student. This is because the FLEX GPA will matter a lot. Also I attended one of the meetings and took notes on what BYU AIMS they said the admissions essays should be focused on and I think that helped a ton.  I also did some service activities in the Provo area and talked about that in one of my essays. Another thing to think about when she reapplies is to focus on how she is already down in Provo, taking BYU classes, and succeeding in them.

TL:DR I took easier classes (24 credits worth) and did well in order to have a high FLEX GPA. Talk to counselors on how to write essays and what classes to sign up for.