Consistency is key! Even 5 minutes per day is good. Over time as you start seeing incremental improvements you get addicted to playing and naturally spend more time practicing.
Yeah, I probably average 20 minutes one day per week. I seem to be building decent spacial awareness or muscle memory on some of the more common frets (3-9) and seem to be getting an ear for standard tuning. Songs with different fret positions (12-15 especially) seem to give me some trouble. I think I just need more consistent practice. It's still fun though. Memorizing complete songs will be a challenge.