Use assonance (corresponding vowel sounds) to create subtle impressions. Assonance can contribute an underlying sense of beauty or grace. It also can create a more obvious emotion when the vowel appears in accented syllables (see Resources below).
Apply alliteration, but with care. Alliteration (repeated use of consonance in beginning letters) can be obvious and distracting. However, when used well, repeated use of particular consonants can lend definite impressions. The letter "L" tends to have a lighter sensibility, whereas other letters such as "K" or "D" sound abrupt. Experiment and practice to gain a sense of sound and how to introduce sounds and the moods they contribute to a poem (see Resources below).
Use subjunctive mood to create contrast or to express a wish or desire. For example, "If I were a butterfly" sounds more wishful and less burdensome than "I am not a butterfly. I wonder what it would be like to be a butterfly?"
Use masculine or feminine rhyme to create impressions of strength or weakness. Masculine rhyme consists of single, accented syllables that rhyme, such as "fight/flight." The added consonance lends to strength. Feminine rhymes are two or three syllables in which the second or third syllables are unaccented. A two-syllable example of feminine rhyme is "pleasure/measure." An example of three-syllable feminine rhyme is "generate/liberate."