I hope this quotation may help you to find your to-do-liste.
- Most good melodies restrict their basic range to no more than an octave-and-a-half.
Most good melodies use repeating elements. Listeners should be
hearing certain melodic intervals, rhythms and other musical shapes
repeating throughout the melody.
Most good melodies are comprised of stepwise motion (i.e., move by
scale steps), with occasional leaps. Melodies that are too leapy are
often too difficult to sing. Good writers use melodic leaps as a
good way to generate little shots of energy.
Most good melodies have a discernible relationship with the bass
line. There are four ways that melodies can move with respect to the
bass: parallel motion (the melody and bass move in the same
direction by the same interval); similar motion (both move in the
same direction by a different interval); oblique motion (one stays
the same while the other moves); and contrary (both parts move in
opposite directions.) You’ll want to mix & match these four ways. By
doing so, you create a bass that feels almost like a countermelody,
and frees up your bass from being overly static.
Most good melodies have a climactic point,down from which it moves
to a cadence (a “rest spot”). A climactic point usually refers to a
melody’s highest pitch, but not always. A climactic point is a
mixture of things: a high note, along with a significant
harmonization, and a strong rhythmic placement, like on a strong
beat.
https://www.secretsofsongwriting.com/2011/03/01/5-characteristics-of-any-great-melody/
and here's a translation of this German site:
https://www.lernhelfer.de/schuelerlexikon/musik/artikel/melodik#
Melody
The main criterion for the unmistakable shape of a melody is its contour, the pure sequence of pitches from which the intervals result. The rhythm and metrics are also important for the individuality of a melody; there are big differences between the melodies of the world cultures.
Historical
Melody (Greek: melos = song, song) is one of the oldest basic elements of music in all cultures. It was part of the development of human social culture: signal motifs generated on animal horns, chants as an expression of social togetherness or in conjuring rituals probably accompanied the development of the earliest human social structures.
The stylistic features of melody are very diverse in the cultures of the world. In the popular European tradition, the emphasis is on formal unity and easy singability, while improvisational elements, microtonal pitch fluctuations or formal openness play an important role in the melody of other cultures. Within the occidental music tradition there are also big differences in the stylistic expression of the melody between the individual epochs.
Elementary melody formation
The main criterion for the unmistakable shape of a melody is its contour, the pure sequence of pitches from which the intervals result. The rhythm and metrics are also important for the individuality of a melody; there are big differences between the melodies of the world cultures.
Example: Melody of a Brazilian samba, next to it the pure melodic contour:
Pentatonic
Many musical cultures and styles have in common pentatonic music, in its original form a kind of call melody, as you know it from the early phase of childish music learning or from archaic blues singing. The sound system and different octave divisions do not yet play a role.
Example: Pentatonic call motif and next to it the full pentatonic scale:
Cultural differences in melody
Different material scales have developed in the world's music cultures: in some cultures, the sound material contains more than 20 levels, others manage with five- or six-tone sound material.
The instruments used are tuned accordingly, and the melodic character of the individual musical traditions differs greatly.
In the western music tradition, a sound system with twelve "equidistant" levels has been developed, which is based on the semitone step as the smallest interval.
Some terms:
Melody and harmony
Many melodies, especially those from the style of folk song and classical music, carry a harmony course that is represented by rhythmically or melodically emphasized chordal tones. Chord-foreign tones are more likely to be found as passage notes on unstressed beats. Numerous melodies contain additional harmonic elements in the form of triad breaks (melodically broken chords).
Example: The theme of “Little Night Music” by WOLFGANG AMADEUS MOZART consists of triad breaks that clearly show the harmonic progression: G major triad upwards, dominant seventh chord downwards.
Character of melodies
Melodies can be differentiated according to their character:
vocal and instrumental,
song-like, recitative, virtuoso-arios etc.