Lots of spiritual work
we've been at it for eons already
You can get peeks of the state with extended meditation (or drugs -- lol!), but you can't stay there until your karma is cleared. I learned that recently, as I kept meditating for hours to get a few seconds of semi-bliss, but once I snap out of it, it's gone.
The Grace (physical presence / aura / field) of a teacher/guru can help clear your karma / boost your LOC. Being in his presence can also put you into that state temporarily.
A lot of this is just raising your LOC as much as you can, either with spiritual work, meditation, satsang with high LOC people who radiate Grace, etc. Highly recommend reading Dr. Hawkins' work, his books talk all about the process.