Good information. I can tell you about my journey and give you an example of how I learn, but this may be a TL;DR. I'm just rambling here, but I love talking about guitar.
My Journey
I've never taken a guitar lesson in my life. I took about 4 years of piano lessons from 9-13, so didn't get into too much theory. I do come from an extremely musical family, so have a natural ear for music and the type of family that always walks by when you are playing to offer advice and tips. When I was 14 years old, I asked my mom for a guitar and was gifted a Squire Strat pack with an amp and guitar. For the next 6 months or so, I tried to learn some songs but never really learned enough to call myself a beginner. I would just struggle to hold down a simple power chord and move it around.
About 2.5 years later, I received a call from my cousin telling me he had borrowed our aunt's bass guitar and he had learned some Green Day songs that weekend, and he wanted to play them for me over the phone. This was 2004 and American Idiot had just released. I immediately rolled my eyes at the idea of my cousin actually playing a song I knew, having just started playing around with the bass. He proceeded to play American Idiot and Holiday for me, over the phone, and it blew my mind that his playing actually sounded like the songs. Sure, there was a lot of fret buzz and I'm sure it wasn't very smooth, but I was extremely impressed. I immediately told him I had a guitar and we should get together to play. Simply hearing my cousin play these songs on bass gave me the drive to learn to play because it no longer seemed like an obstacle I couldn't overcome.
I went over to stay with him that weekend and we proceeded to learn multiple songs from that album. That was some of the most fun I had ever had up to that point, working through guitar tabs and learning how to play my power chords and move my hand up and down the neck to actually make some music with my cousin. I'm sure my aunt and uncle got sick of hearing American Idiot and Holiday over and over.
From that point, it became something we would do at least every other weekend. In between our jam sessions, we would work on more songs and then I would go over to his place and we would play those damn 4 power chord songs for hours. We continued with this for the next year and a half before I left for A&M.
While at A&M, as with many of my friends, my music discovery started going backwards instead of what was playing on the radio. Popular rock was waning and I started soaking up classic rock like a sponge. This was when my love for Zeppelin started to grow, as I pirated all those albums (18 yo me). I started wanted to learn those songs now, which were much more complicated and pulled me out of my power chord comfort zone.
I tell that anecdote to illustrate that the best way I have found to learn to play guitar has been to learn songs I love. Simply sitting down and playing scales is the most boring thing in the world. Is it helpful to get better? Of course. Should you learn where every note on your fretboard is? Of course. But those are things to learn to move from Intermediate guitar player to very good guitar player.
Right now, make guitar a joy in your life. It should make you happy.
My Recommendation
Fair warning: I am not a guitar instructor, so take anything I say with a grain of salt. I'm just telling you what worked for me. Also, the benefit of an instructor is they can critique every aspect of your playing that you may not recognize. For example, are you fretting your strings to heavily, causing your chords to be too out of tune.
First of all, your guitar should always be out on its stand. Your guitar should NEVER be in its case unless you are traveling somewhere with it. You should see the guitar as you go about your day, and you should want to go pick it up every time you see it. I've never smoked before, but I feel like my compulsion to pickup my guitars every time I see them must be what it's like to want to take a drag on that cigarette as a smoker.
If you can afford a guitar you really like the look of, then you should buy that guitar. We get a lot of questions over what guitar is great for a beginner. The answer is any guitar that makes you want to pick it up and play it.
What would I recommend? Pick a song to learn. Don't go picking some ridiculously hard song or some song that an instructor wants you to learn. I have a friend who was learning guitar last year, and her instructor was picking all these songs that she had no interest in learning, and she never showed much excitement in going to her lesson. I asked her what she would want to learn to play and she said Sweet Home Alabama. I told her then that's the song she should learn.
If you can learn a song with someone else, it's more fun.
Once you learn the song, then take the time to understand what you just learned. What key is the song in? Why are those chords in that order? Was there a solo? Why were those notes for the solo chosen? After learning the solo, recognized the shapes. Many rock songs are just playing around a pentatonic scale in various positions. Understand which position you are in during each part of the solo and it will help you understand the rest of your fretboard so much better.
It may sound cliche, but I think Stairway to Heaven is one of the best songs for a beginner to learn how to play, and it's one that taught me so much about playing guitar (just don't bust it out in a music store. Stairway to Heaven should only be played in the privacy of your own home).
This is the exact process I go about when learning any new song, and it is how I've learned to play guitar:
Know the key of the song. Stairway is in Am, so you get to learn a lot of very common chords. The pentatonic scale for that key is also in easy-to-remember positions as you are working on those shapes and learning how the pentatonic scale works. The beginning of the song starts with a fantastic descending chord progression played in arpeggios. This teaches you fingering of different chords, variations of chords, and the technique of individually picking notes in a chord (arpeggios). Being able to pick a string you want to pick, and making sure no other string makes a sound is a foundational technique in guitar playing. This must be learned, and you should play whatever song you are learning over and over until you can mute the strings you don't want played, effectively.
After completing the descending scale, you then have to immediately slide back up to repeat the progression. This whole process will teach your fingers importantly positions for muscle memory, but will also help with the speed at which you move between chords..
The second phase gets into strumming. You lean to strum some of those chords, and then you also learn very important lessons on chord voicing. There are measures in the second part of the song where, in order to sound like the recording, you realize you need to strum upwards and not even play the lowest root or 5th of the chord. This is very important in teaching you different voicings of chords.
As you play this section, and every other section, it's also important to listen to what you're playing. One of my favorite things I have ever seen on guitartube is in a MusicIsWin video where he is teaching his wife how to play Brain Stew on the guitar. She proceeds to play some things he shows her, then looks at him and asked if that was correct. His response was, "does it sound correct?" That question may sound tongue in cheek, but it highlights one of the biggest issues I see with so many people. Don't focus on simply playing a song. Actively LISTEN to what you are playing. Does it sound like the recording? No? Then find out why. Sure, Page is playing an Em chord. However, when you play an Em chord, it sounds nothing like page. So what is he doing differently? What inversion of Em is he playing? How is he strumming the chord? Which string in is he muting?
The next part of the song is the solo. This will take time to work through, but it is worth it when you finally do. Break off one measure at a time. Learn your bends. Learn your shapes. Learning to bend notes a full tonic is extremely important. Again, listen to what you are playing. I'm heard many people who must think they know how to bend, but they are always flat because they haven't practiced enough to understand where that tonic is.
After working through the solo (which may be the last part you actually learn) you then get to the last section of the song, which is straight up power chords. Root, 5th, and octave. Everyone needs to be able to hammer out some glorious power chords. You do not play the 3rd when playing a power chord. The 3rd muddies the chord and you lose the "power".
Every technique I have learned on guitar has come from learning songs. I learned my power chords from Green Day. I learned my arpeggios from Stairway and Simple Man. I learned to solo with my pentatonic scales and how to transition between positions from Stairway and Hotel California. I can go on and on across all the songs I've learned in my life.
Every other song I learn I always try to take something away from. If you have questions on certain songs as you are learning, bring them to this thread and I'm sure many of the posters would be more than happy to provide some feedback. NGD thread is the least toxic on this forum, and everyone is happy to help.
Anyway... enough of my rambling. I need to get back to work.