although some instructors say place your index finger down first, a lesson I saw by David Taub, nextguitarlevel.com, was helpful. to first learn the barre, finger an E major chord with 2,3, and fourth finger. rest the index on the nut. next slide the chord up one fret and then lay the index finger down as straight as possible by dropping the wrist, and yes tilting the keyboard upwards helps to lay the finger down straight. do this to strengthen the proper position rather than strengthening a crooked index finger. Remember i'm just repeating what David Taub is teaching.
I'm just starting 7 and this will take a longer time to master and i'm committed to daily practice. I'm finding that using my fender with 9's is the easiest to barre as i develop muscle memory and strength i'll try, as has been suggested ,to work up to my acoustic. Just sharing my observations I'm struggling like the rest.