Also review the several conventions concerning three voice writing. Remember that all three voice chords must have the third of the chord present. The complete triad (all three notes) is desirable, but sometimes voice leading makes it awkward to maintain this texture. Usually if all three notes are not in the chord, the incomplete chord has the root doubled. Occasionally the third might be doubled (vi in a V to vi progression), and of course the tripled root is possible on the final chord of a phrase if the progression is V to I. Recall that in root movement of a second, in three voices, the structure of the chords will alternate from complete to incomplete or incomplete to complete. Also in root movement of a third upward one needs to be certain that the second chord is complete (includes the fifth).
By far the most common errors in partwriting are dealing with the leading tone. First, one must be sure that an accidental (creating the leading tone) is present in the dominant chord in a minor key. Then assure that the leading tone is not approached from the submediant (aumented 2nd) nor goes to the submediant. Most often the leading tone, when it appears in the soprano, goes directly to the tonic (both major and minor keys).
If you still have questions, contact Dr. Bartolotta at file:///E:/wbartolo@odu.edu