finding cervix

Hi! I am a FNP student and no matter what technique I use, I can hardly ever visualize the cervix during speculum exam. I have tried angling the speculum downward on insertion, going back as far as possible and opening the speculum and gradually aiming upward, having patient put their fists under their buttocks, taking the speculum out and inserting at another angle, and I've tried feeling for the cervix first. Nothing works for me!! And for big women who have lots of fat in the vaginal canal...is a condom on the speculum the best approach? Are there any techniques any of you can share?

Thanks so much!