In answering this so ubiquitous a question, it would probably be most useful to elucidate some of the central guitar techniques that you are likely to come across in your first few years of learning the guitar. If you have a strong hang of these different techniques, then chances are you are either well on your way to learning fingerstyle guitar strumming or are not going to find it too much of a problem when you come to face it for the first time.
If you can already hold a pick this is great, and you can move on to the next of these guitar techniques. If not, then either continue to heed these words of advice or do not heed these words of advice, if latterly you are intending to play fingerstyle most of the time.
The goal is to have a firm grip without exerting your finger so much that it is an uncomfortable experience, typically pivoting the plectrum between the curled index finger and the thumb, using each as an axis. The various gradations of holding a pick in this way, not to mention the specific plectrum that you end up using, is largely down to personal preference and choosing a guitar pick that is right for you, much like the way a child’s own preferences are developed in the early stages of their life, will be determined by the progression of your earlier moments of learning the guitar. Thus, you ought to proceed with caution.
Striking a balance between firm and loose is the goal here and will very much depend on your own grip and playing style. If you are seeking to play faster note runs, you will require a looser grip, much like that of a drummer. The inverse is true for a guitarist who is more into heavier riffage and chordal progressions, wherein a stronger grip will be necessary to enact these things with as fierce a vengeance as possible.
Though this is one of the more basic skills that a guitarist will come to use in their tenure as a musician, it is easily done ‘wrong’ and contributes to a large number of cannon fodder musicians falling prey to impatience and bad form. I would never usually say that there is any right or wrong way to do anything, though fretting in particular ways early on can quickly lead to the development of bad habits, bad habits which can not only affect your ability to play but can go on to affect your joint and muscles, in some instances harbouring carpal tunnel syndrome.
You should strive for a light touch when fretting in order not to hurt your fingers from playing. A useful exercise at the beginning of your development as a guitarist is to fret a note as hard as you can and then slowly take off the pressure of the fretting hand, plucking all the while, until the note no longer sounds right and is marred by fret buzz and the like. Finding an equilibrium in this way is the best way to make sure your notes are sounding clean without over exerting your wrists muscles and joints.
Another of these central guitar playing tips and one that you are likely to come across wherever you go across the world is that of the hammer on, a technique that means the notes are not inherently separated by plucking. In precise theoretical terms, this is referred to as a legato between notes, wherein the notes are sounded out so as to connect smoothly instead of being separately plucked.
In musical notation this arises as a slur between notes, though in tablature this is notated with a more obvious letter ‘H’ beside a series of notes.
With all these symbols and terms coming at you, it can be easy to overcomplicate what is, in fact, a relatively simple and ubiquitous guitar technique. In essence, a hammer on is simply the plucking of one note and then the fretting of other note under the same behest as that note plucked previously. Try plucking any note on the guitar, and then fretting another string higher in pitch by however many semitones you like, and you will have used a hammer on.
The same very much goes for the act of pulling off, though this is approached from the inverse. Where a hammer on is the legato smoothness of bridging the gap between two notes from lower to higher pitch, the pull off is the exact opposite, connecting two notes from a higher to a lower pitch, ‘pulling off’ one’s finger from the higher pitch to the lower pitch.
So, instead of playing a note and then placing another finger onto the fretboard on another fret afterwards without plucking anew, the note will be plucked on a fret, and then the finger will be removed whilst another finger is present lower down on the fretboard, so that this new pitch sounds without the need to pluck anew.
Pull offs are notated in much the same way as hammer on’s, exactly the same in musical notation in fact, and with a ‘P’ instead of an ‘H’ in tablature. Certainly, these things can seem difficult when described in the abstract like so, but if you were to fret a note with your ring finger, pluck it, and then remove it whilst your index finger, say, was placed a fret or two below in pitch, you would be committing the heinous act of pulling off.
Once you have mastered the aforementioned guitar techniques, you can move on to bending your notes. This can take a little more getting used to, hence why it is best to have hammering on, pulling off, plucking, and picking under your belt first, and why you should have this under your belt, too, before proceeding with fingerstyle guitar.
In essence, bending is what it says on the tin: bending a note to alter the pitch, either up or down. The reason this takes a little getting used to is that, unless you are intending to make music that is more left field, experimental, or microtonal, then accustoming yourself to the right pitches is vital to ensure that you are bending the right amount to still be in key with a song that you are playing.
As with all things this takes practise, especially if you are intending to pre bend. Where normal bending is the act of bending from one plucked note up to another, the act of pre bending is to be bending the string before plucking it, thus lowering the pitch in a portamento way. To do this, you will need to have a learned understanding of pitches and fingering positions.
Much as with all of the other guitar techniques mentioned thus far, the act of sliding between notes will be enacted on one string mostly, at least for today. Similarly, this technique can be deceptively difficult to master and requires, as with those guitar techniques aforementioned, considerable practise and a strong understanding of pitches and spatial awareness on the fretboard.
In essence, sliding between notes is as simple as plucking a note on the fretboard and ‘sliding’ the fretting finger up or down to an alternate pitch. This can be difficult to master, certainly, though can yield some very interesting results, especially with those more adept with the technique. Some can even imitate eastern instruments like the Sitar using the rapid up and down sliding that this technique offers. Blake Mills, as seen below, is a master of using these simple guitar techniques to devastatingly effective and unique results.
There are two kinds of slides in western music, both of which differ from each other in considerable ways. Where a legato slide is simply the act of plucking a note and sliding to another, a shift slide is the act of plucking a note and sliding to another and then plucking this new note.
And so, we arrive at arguably the most difficult of the guitar techniques here arrayed, and surely among those that are going to guarantee your progression to fingerstyle guitar, should you indeed manage to master it.
Using vibrato has much in common with the act of bending, though instead of plucking a note and bending to or from, the vibrato technique involves plucking a note and vibrating up and down while still using the very note initially plucked as a focal point. This can be likened to the action of an opera singer’s voice, wherein the note is held though wiggled up and down for dramatic effect.
Since its inception into the guitar canon by such proponents as early blues musicians and B.B. King, it has spread rabidly among guitarists the world over, so much so that it is quite rare to find a guitarist that is not lathering their own playing style with such techniques.
Try plucking a note and twisting your wrist side to side while still holding on to the note and you should, with a little practise, be able to get where you want to be in no time.
So, there you have it! Hopefully, as you have progressed through these techniques, you have garnered a stronger understanding of just exactly what makes these guitar techniques tick, and has emboldened you learn and master some of these techniques for yourself and readied you to take on the almighty fingerstyle guitar!