The title of this tip is based on something my father used to say to encourage me when I was about to sit an important school exam. 'Put your best foot forward!' Or in other words try your best and make the most of the things you have prepared well, towards the best possible outcome.
The same attitude serves us well when making right hand fingering choices while learning a new piece of guitar music. Over time you will undoubtedly discover that there are some finger combinations that work well for you and others that don't happen so easily. Of course, this varies from player to player, depending on experience and repertoire already successfully played, along with the variety and frequency of technical exercises studied. It's also fair to say that the efficiency of any player's right hand technique is also determined by finger sizes and shapes, dexterity and not forgetting also the characteristics of fingernails.
There are different right hand techniques that can be adopted. Playing from the left side of the fingernail, playing from the right side, the angle of attack, the positioning of your thumb in relation to the fingers; all affect the comfort of different fingering approaches. It follows that a renaissance lutenist who alternates thumb and index finger for scale playing would make quite different fingering choices compared with a classical guitarist who alternates i and m fingers, for example, following the Francisco Tárrega school and others.
But going back to the title, 'put your best finger forward'; it's important to give careful thought to which finger is right in any given situation. It sounds obvious but it's easy to overlook just how necessary careful right hand preparation is. On the most part, simply ploughing ahead hoping for the best leads to mistakes creeping in and worse, mistakes being memorised.
That said, it is of course fine and necessary to play through a piece without prior fingering preparation when you are simply exploring repertoire or testing yourself with a sight-reading challenge or exercise. Depending on the complexity of the piece, and no matter how good a sight reader you are, you will eventually need to stop and carefully consider right hand (and indeed left hand) fingering options. The speed and efficiency of deciding on the most effective fingerings naturally varies depending on the amount of experience and training any player has under their belt.
Choosing the right or best finger at the start of a melodic phrase or scale, for example, is beneficial and sometimes critical. When deciding on that start finger, you might need to consider what happens further on into the phrase or scale. Somewhere along the way, you might find for example a change of string is necessary which might require a specific finger alternation in order to efficiently and reliably play across the strings. This is most critical when the aim is to eventually play the phrase at a fast tempo. You need to be sure that the string change can be played smoothly and accurately at the required tempo.
Of course, moving between strings might be second-nature to guitarists who have completely mastered playing with all finger combinations across different strings at all tempos. But not all of us are created equally and for most of us preparation is the key to achieving a successful guitar performance.
It's worth mentioning too that there are occasions when right hand finger alternation is not only unnecessary but doesn't produce the best sound. A more consistent tone, which is important when shaping a melodic line, can be achieved by repeating the same finger (usually the one that produces your best sound.) However, the approach is usually only appropriate when playing a melody at a slow or moderate tempo and depends on what else the right hand is required to play.
Putting your best finger forward - be it i, m, a or p - is a great way to start!