Hey guys-

So, here's the story-  I've had guitars for 25 years, but never taken lessons- just tried to learn stuff by ear, learned a couple chords, etc.

Recently, I decided to start lessons, and hopefully finally try to figure this out.

I've been working on basic string fingering, like frets 1-4 on the first string 1-4 on the next, and all the way up (or down, depending on how you look at it)
and also basic pentatonic scales.

I started doing this on an acoustic guitar, but I started progressively getting worse, regardless of how slow I played. I got mad that I really couldn't see the fretboard,
and switched to my electric guitar where I can.  I still am having problems getting my fingers to go where they need to be, picking the wrong string,
or picking at the wrong time that I'm fretting a string.

It's hugely frustrating, and I feel like I'm not getting any value out of my practice time.  I know that learning takes time, but I'd like to think I shouldn't be getting worse than when I started this exercise-

Any advice from those of you who are more experienced?

Any input is appreciated- Thanks

Go slow, really slow when you're first learning something. Then gradually, and I mean gradually, pick up speed until you screw up. Then slow back down and start all over again.

Yep, the above is correct. To give you an idea of the time required, if I'm learning a challenging passage in a piece and I want to play it as recorded it might take me 3 to 4 weeks of practice before I can pull it off.  For me it is not a quick process.  But I've done it enough to know that if I keep with it, somewhere around 6 weeks I'll wonder why I thought that passage was difficult.

Playing is still hard work for me. The older I get the harder it gets.

Electric guitars are more forgiving because you just have to lightly touch the string to get a sound and the reverb helps blend the notes.  

Acoustic needs you to actually finger the note.  If you are used to electric, you are probably just tapping the notes on the fret board and not paying attention to the fingering.

As others have said, slow down while you focus on proper intonation.  If your acoustic is not progressing, maybe it's not the right acoustic for you.  Go browse your local shop for other brands and try them out.  Maybe you will find an acoustic that feels more like your electric with the frets.

Try a set of 11's on it too.  May help with the intonation.

It sounds like fatigue. Check the action of the neck.

I played with the idea of trying this

Learn to tune your guitar correctly. Buy, borrow or steal a pro level guitar. Low action, correct intonation, and good sound.

sell or burn the junk.

Learn chords in the first position. Cowboy chords.

Pick a song. Any song. Learn the chords for that song one at a time.

Then learn the chord changes.

The guitar has to not punish you.

Don't press too hard it de tunes the strings and hurts.

It's tough starting out I won't lie. It hurts, is depressing, and sounds like shit.

But it is worth it. There is a hump you will pass. It won't hurt anymore.

ETA been playing 38 years. I think I sound like shit, but listeners disagree. Don't judge yourself, brother.

I found it is difficult for me to play a dreadnaught for any length of time. I tried and tried but just cannot due to my shoulder. I purchased a parlor guitar and it fits much better and I do not get the discomfort. I do still gravitate to the electric.

Many will say that you will progress faster on an Acoustic and this is true to a point. However if you love to play electric then play that. play what ever you will paly the longest.

Try a basic Pentaonic Scale and learn the fingering it is very easy. Play this very slowly until you can play each note cleanly. Speed is not your friend. Slow and clean beats fast and crappy. Once you can play each note cleanly slowly ramp your speed up. Now learn the other positions.

Minor Pentaonic Scale

I agree with the other poster, sounds like you're fatiguing. It's no big deal, happens to everyone. At that point, if you're getting frustrated, just put it down and come back later. It's no fun that way.

I am no pro by any means. But, some days I can do no wrong... and other days I can do no right.

Another thing that helped me is leaning some very easy songs. Songs like Enter Sandman, Iron Man, Smoke on the Water, etc. Sometimes helps to take a break from doing mundane scales over and over as well...