OK, I am on Beginner L1 module 5 learning the “Come as you are” riff and I am having this annoying problem sometimes of hitting the D string when I need to hit the A string. It also happens some when strumming chords and I only need to strum 4 vs 6 or 5 vs 6 strings but is more annoying when working on the riff.
Is there a magic elixir I can drink to solve this?..OK I know there is none but there’s got to be a specific exercise to work on this issue.
ANY help is appreciated. Thanks…
Practice! your really just starting out, consistently hitting the right strings is hard
For chords you can mute the strings you dont want
Hello Mark,
Welcome mate. Not sure if I’ve ‘spoken’ with you before.
Yes, its early days, so a very common issue I’d say every single person faces. Focused practice, as usual, is the answer.
For strumming, one thing that helped me early on was an image of a plane coming into land then taking off again. Applying that sort of motion helped me to start consistently hitting the strings I wanted to, and set me on my way.
For picking, think about picking in more of in/out motion, rather than strictly up/down.
Early days though mate for both. Keep at, reach out here anytime you need , ( and be kind to yourself ) 
.
All the best.
Cheers, Shane
I believe right hand and left hand accuracy should go hand in hand and you could broaden up the “accuracy” exercise a bit to develop something you can build on.
First:
Lessons on how to hold a pick; review those first as it is hard to unlearn bad habits.
Then, check out how “all over the place” your picking is and try to include some of this in your practice:
As an exercise, the Spider can be an interesting challenge, once again to work on those economics
Then,
try some alternate picking, not only is this a great way to boost your picking economy, it will also improve your accuracy…because only by keeping your picks small and accurate, you can succeed.
Dont worry if alternate picking still feels to hard for now.
It’s the sense of keeping the movement small that will help your general accuracy
These lessons will work on your technique, a cleaner, more accurate and energy preserving base layer for your further guitar career 
I would add to the above to spend time practicing just the picking pattern, even if just alternating 2 strings, with the right hand only (to a metronome, ideally). Leave the left hand out of it for a little bit. Trying to learn left and right at the same time, especially with an added metronome, is a lot. A little time just doing right hand practice, then left hand practice, before combining, will make a difference.
This is the whole idea of the lesson, is to teach you pick accuracy. Slow it down and practice it correctly. Justin could have given you a boring exercise but chose to teach you a riff instead.
Hey Mark!
THIS!! 
If you do it, the skill will come!
Enjoy the ride!!
Thanks guys!! Yes, straight up persistence and grinding away last night till 5a.m. and not smashing my guitar like Pete Townshend when I got frustrated has won. I am now working my way through the riff moderately fast 2 or 3 times before making a mistake.
Just had a big LOL moment about your Pete Townshend comment. I have definitely been there!