The first is the brushwork. Or aesthetics, if the words are written and others shake their heads, then no matter how good the composition and printing are, there is no hope.
Second, the layout. Some people think that layout is part of composition, but I don't think so. Before writing a calligraphy work, we must first make a virtual layout, especially the opening layout is very important, which word is in what position, which font is good, the density of lines, the amount of blank space, where the inscription is, and so on. With a good layout, the work is half done.
Third, the rules. Including the echo of words, the arrangement of density, the weight of pen and ink and so on. Composition is gradually accumulated, and you can also learn by reading and copying good works.
Fourth, use printing. Writing articles pays attention to anticlimactic, so does calligraphy creation. Don't underestimate the use of printing. When printing is used well, it is the finishing touch.
My knowledge is limited, I hope it can help!