I've been in Shinjuku few times, I've always got lost.

Found a "hack" where I would go upstairs to the mall and then go down closer to the spot I need.

Shinjuku is way too massive (and now has plenty of diversions due to work om the station itself) to be understood easily by a tourist.

I always tell friends to just go to any east exit and make their way outside. That's most likely where they're headed and it's easier to navigate outside the station than inside.