I never mastered any of this. I love playing but my varied experiences have left me with limited abilities. For many years I have compared myself to accomplished professionals and lamented my many flaws. For example, my teachers often chastised me for playing by ear or memorizing instead of reading the music. I have long accepted this as a weakness.
During the past couple of years I have realized that the opposite is true. I am not saying that I don't have room for improvement. What I have realized is that I need to use my abilities to my advantage and compensate for my limitations.
Here are a few tips and tricks that I have learned from experience.
1. Play through a hymn first. Sometimes I surprise myself. Something a hymn I thought was unfamiliar or difficult turns out to be quite simple. Once I determine the difficulty and my ability to play the hymn as written, I decide if I can make it work.
2. Like most novices, I can play better with my right hand. I could play almost any hymn with just that hand but it doesn't sound complete. I prefer not to do this. One way to alter a difficult hymn is to just play whole-note chords with the left hand. "Love At Home" (Hymns, 294) is an excellent hymn for this trick. In the first measure, I would play the first notes as a whole note, the second measure I would play the first two chords as a half-note and the other half note as written, and so on.
3. Sometimes I simply can't reach all the notes, especially in the bass clef
(the bottom, left-hand notes). I have found that playing the very bottom notes, along with the upper, right hand notes, creates a fuller sound but is somewhat easier to play. It takes practice to figure out which notes to play and which to leave out. Some examples of hymns that work well with this trick are "Rejoice, the Lord Is King" (Hymns, 66) and "As Sisters In Zion" (Hymns, 309)
4. Sometimes the hymn is written in a key that is hard for me. Now you can go to LDS.org and transpose the hymns into a different key with the click of a button! Just print it and play it. Most people won't notice and those who do should keep their mouths shut! What matters is that it helps you fulfill your calling and invite the Spirit into the meeting. *Note: be mindful of the vocal range of those singing. If it is too high or too low it will be uncomfortable to the singers and detract from the music.
Example: "How Firm A Foundation", (Hymns, 85) is written in the key of A flat Major (4 flats). By clicking the down arrow once, it is in G major, with just one sharp. But if you continue adjusting up or down you not only get lots of sharps or flats but the song will be in an unrealistic vocal range.
If you have been called and set apart as a pianist it is up to you to find a way to fulfill that calling. An don't forget, music is a creative art form. So be creative!