For some reference, here’s how I hold a pick for strumming-
If I’m picking strings, I’ll hold it similarly, but just with less pick exposed.
If switching I’ll subtly let it float in/out as required. And if strumming slowly, I’ll even sit and spin it between my fingers as I am quite a bad fidget 
WRT to pick spinning around…
Justin’s funk course has an exercise buried in one of the lessons that helped me quite a bit, even though I have no interest in playing funk.
Basically, you deliberately let the pick rotate a full 360 degrees, in either direction. Once you learn to control this, you seem to learn how to prevent it from happening, and also get it back in position if it moves.
The exercise is around the 6 minute mark.
Between 5 and 6 years into learning guitar with JG and I’m wondering if I’ve been holding plectrums the wrong way all this time. I think I always follow the way Justin describes holding them between thumb and forefinger but someone I met the other day pointed out that my remaining fingers should be curled into my palm. I’ve never considered the other fingers before and now I do I see I keep them straight when strumming. I guess I always have. Returning to JG’s video he doesn’t mention the other fingers but I see he curls his into the palm as I was told I should the other day. Are there any pros and cons to this or is this just a distraction? I should say when I do curl my fingers into the palm it doesn’t feel natural and I will have to learn strumming all over again, almost from square 1.
@Willsie - I also have my other fingers out in the air and never given it a second thought.
I have gone over several videos now and see both. Seem to be nothing right and wrong in this sense. - Maybe it’s just a person who is jealous of you and just want to correct you for no good reason 
There are benefits to have the fingers out if you alternate between strumming and picking single strings.
If a person tells you, that you are wrong not having them curled up, then please let that person tell Paul Davids and Troy Grady and many others, that they are doing it the wrong way
Think you should just do it the way you find best
Its funny that you are asking this question as I’ve also been wondering if I’m doing it wrong … I mostly have my fingers curled under. Mostly I find that this gives me better control of the pick and I can easily keep it from spinning around or otherwise getting into odd positions. What led me to question if curling was wrong is doing individual string picking exercises such as Picked Fingerstyle | JustinGuitar.com where the pinky is anchored.
I’ll be watching for responses to your query and I hope the right answer is “it depends”
Cheers
Glen
hi John,
Justin says you should always ask “why?”. Did you do that? 
What I have noticed is that the folks that need to speed-pick like to curl up fingers, even the one holding the pick. Check out Bernth’s Youtube commentary on it here, and here. Part of it seems to be that you can go faster with less moment arm of fingers flapping around, and you tend to not scrape strings which makes unwanted noise.
I tend to have fingers partially curled up. I like to be able to extend my little finger down as an anchor. If I grip like Bernth suggests, I cannot strum very well at all - too stiff. So my approach so far is a balance for what I am doing.
Just pick the best approach for you…
I agree, but like to be open to alternatives, especially if they turn out to be an improvement.
I tend to use the little finger as an anchor when needed.
That’s what I hope to do.
I totally understand you. I also look for alternatives and look, read and hear how others do it and try out many different ways, until I find what feels best for me. I just replied more to that sentence you made there. I feel strain in my arm when fingers are curled up and I can still use middle finger to correct the pick while keeping the strumming, despite having them out in the air.
I am lucky to be somewhat beginner only having +200 hours in. I can imagine how hard it must be for you to change after 6 years. So if it works for you after 6 years, you are certainly not doing anything wrong. You play so nice, so how could it be wrong!? Just checked your Harvest Moon clip from last year. 
- I have my fingers something like that also, and works totally fine.
Still holding the pick as Justin suggest.
These good teachers have 2 things in common, have fun and find the best way for you.
When I use a pick I tend to hold my fingers in a relax half curl but I also hybrid pick a lot so having them staight or a tight curl wouldn’t be very convenient for me.
I’d suggest which ever is the most comfortable. If your using the pinky as an anchor sometimes having them straight would probably be the best way for you.
@Willsie
Hi John, I’ve been playing a few years less than you so take what I say with a pinch of salt. My view is that if you extend your fingers all the way out you will feel tension. If you curl them up to form a fist you will feel tension. You don’t want to play with tension, that’s just not good at all in your playing. @stitch uses the key words “relaxed”.
When I am picking scales (like in a solo), my fingers are gently, but completely, curled under. When I am strumming with a percussive hit to the strings, my fingers are extended and relaxed. When I am strumming chords and letting all the strings ring out, my fingers are gently, but completely, curled under. When I am targeting individual strings while strumming, I anchor with my pinky and the other fingers are partially curled.
There is no right or wrong, there is only what feels right and what best fits the situation. I always suggest trying all different ways in all different scenarios and choosing what works best for you.
YMMV
I know that some players use the little finger or ring and little finger to touch the body of the guitar below the strings to help control the height your hand is above the strings. On the other hand, others recommend not touching the body of the guitar with your strumming hand (this doesn’t include right hand muting on the strings) for maximum freedom. I believe in using what works for you, but keeping in mind others have been there before you and if most players go one way, that’s probably the right way for you. All this stuff takes concentration and awareness to develop the technical physical skills.
You can do it. That others have done it is the proof, but you have to work at it.
Good luck,
Just_Dan
Good luck
Hi Justin and community,
I think there’s a missing topic for beginners for which a video discussion/demonstration would be appropriate. That topic is Flat Pick, Thumb Pick, Fingerstyle or finger picks. I think it’s important to inform beginners that if they choose to flatpick, they’ll likely need to learn hybrid picking (or get very, very good a flat picking) to play a lot of songs (e.g. Stairway to Heaven, Page uses hybrid picking) and learn to not drop the pick. Travis picking with a pick, again not easy. Merle Travis used a thumb pick, as did Chet Atkins and others. And I’m not so sure the advice to choose the method based on your personal guitar heroes’ choices is correct, nor is the advice to choose a method based on the style of music you plan to play: Freddy King used a thumb pick and finger picks, Albert King used finger style, and SRV/Albert King used a flat pick and maybe some hybrid picking, I don’t know for sure, but when 3 major players in one genre use different methods, it argues against the “choose a pick based on your song genre”.
Further, there’s a big difference in your ability to play certain things with these different approaches. You can’t play two or more strings simultaneously with a pick compared to finger style, but a fast pick stroke can almost make it seem the notes ring simultaneously, but it doesn’t sound the same as plucking 2-4, or even 5, strings simultaneously with finger style. There are fingerstyle guys who’ve developed the ability to play bass, rhythm and melody all at the same time (e.g. search for “Naudo guitarist” and watch the guy) similar to how Chet Atkins does it with Sandman. Do beginners know they can’t bend a string 3 frets up on an acoustic but not an electric?
It’s not that a beginner will be able to do this any time soon, it’s that they should know the options in their journey, and to where they can lead, easily or with more difficulty. Instead I think teachers are inclined to push what they know. So, Kudos to Justin for teaching both plectrum, finger style and hybrid picking.
Personally, I believe a lot of beginners would like to know the probability they will continue playing after about 6 months of effort, for the different methods. Anyone know? What I read, is that after a beginner buys a guitar (average price (~$600) after 6 months 90% of them give it up.
@robd12
You have far too much of the pick sticking out from your finger & thumb.
See here for pictures I posted earlier in the discussion for a better grip.
@Willsie I advise against curling the fingers up. It can cause tension in the hand and fingers (like curling a fist) and it also makes palm muting impossible. Relaxed and easy is the way for me. let your fingers unfurl.
John, I have seen Justin hold the pick different ways depending on what kind of strumming techniques he is doing. It is harder to do some types of strums with the finger curled in. I have also seen it taught both ways on other guitar instruction videos. I have decided that curling my fingers tight creates too much tension for me, so I tend to keep my fingers loosely curled. Sometimes you need to have the 2nd, 3rd and 4th fingers extended for percussive strums. I just noticed that @Richard_close2u said the same thing, so it must be right (I need to learn to read all replies to a posted question before I respond).
I have a classical guitar. Do you recommend using a pick with it?
@YelizTheMenace Hello. Welcome to JustinGuitar and the Community. You can 100% learn on a classical guitar. Playing nylon strings with a plastic pick may sound different to your expectations and you will need to experiment with it. There is nothing wrong with it per se. You can even buy felt picks for nylon strung instruments.