3 important topics guitar learners should focus on?

strings and tuning, open chords and rhythm, notes and where to find them, what notes make each chord, major and minor scales.

Proper fingering , constant tempo and having fun !

Chords, Scales, Grooves. Then the combinations.

I think this is an excellent question - I get similar queries from my students all the time. Also, the folks here already gave you some really good input which I can only echo.

In essence, here is what I keep telling my students:

1.) The quality of your practice is just as important as the quantity

As a rule of thumb, I tell my online guitar students to pratice 20 minutes a day, six days a week. However, I also put emphasis on making sure that while they practice:

- they are in a quiet environement by themself
- absolutely no distractions (facebook, email, tv, cell phone)

2.) Play clean and accurate

As you learn your first chords (typically open chords), don't just strumm, but also pratice a new chords by picking each string individually. That way you will be able to identify and eliminate subtle inaccuracies which you won't necessarily hear by just strumming the chord. I'm talking about things like accidentally muting strings, playing 'on the fret' instead of 'in the fret', etc.

3.) Use a metronome

Yes, I hated that thing, too - especially in the beginning. But I cannot stress enough how important it is to incorportate using a metronome as you practice a new piece. It goes a long way, believe me.

Oh, also, make sure that your hands are clean and nails are short.... :)

1.) The quality of your practice is just as important as the quantity
I agree with this, it is vital if a beginner is to continue playing.

2: Chords (open). With this I would encourage a portion of time be set aside for practicing movement from one chord to another whilst the strumming hand does nothing.

3: Strumming and picking. The strumming is to enable the student to learn a song asap and the picking is to make sure the chords sound clean.

Yes, unfortunately I know too well that a lot of students have their Facebook or other distracting things open on their computer while they practice. It is so important, though, to really make sure that the environment you're practicing in is conducive to the task. Especially in the beginning.

Everything is covered as it seems here but I'll add from my own mistakes. Long story short, I've been playing for a very long time... but never played it good. lol Only recently have I started to focus on it. So with that being said:

Have a reasonable goal. In business we call it "SMART" goals which means: Specific, Measurable, Achievable, Realistic & Timely. :)

LEARN THE FOUNDATIONAL STUFF. My biggest mistake was trying to jump into Slash style solos, realizing I'm not Slash after noodling for a while and giving up! lol Foundations include: basic chords, having rhythm, ear training, knowing the notes on the fretboard, then moving to scales and such if that's your thing. Music theory in here somewhere too, although I'm trying to avoid theory, I can't help but be forced into it. I suggest not fighting it like me right now.

Learn to warm up before practicing/learning for hours. Good habit to have.

Know that it will sound only as good as the amount of work you put into it. Any great player started from zero, they got to that level because they put in countless hours into it. So don't let some jerk that has 25,000 hours put you down or don't get discouraged by not being able to follow the greats note-for-note yet... you'll get there!