BE SUBTLE WHEN IT COMES TO EMOTION, lest it is perceived as manipulative. The reader can be inspired to feel deeply without being pushed to it. Over-sentimentality tends to trivialize the subject, make it sound mushy, where much better can be achieved by inference and suggestion.
Also beware of rhythm and rhyme, unless your poem is light hearted. A serious theme can be overwhelmed by any lilt, and only exceptional poets can satisfactorily achieve such a combination.
Various poems have various aims, regardless of the topic. Decide what you want your poem to convey, your ideas, opinions, statements.
It may be about the elements of nature, a protest against war, be autobiographical, or take one of many other directions. Whatever direction you decide to take, make it a fresh path; readers become tired of well worn paths. Use fresh metaphors or similes, original phrases.
A cliché often seems the best way of saying something, but think beyond its boundaries. If by ‘opening a can of worms’ we wish to convey letting loose many undesirable possibilities, perhaps ‘disturbing a nest of wasps’ would give a fresher image.
This also applies to use of the senses. It is valuable to incorporate sight, hearing, smell, touch, taste, and kinetic sensation, but try to be more original than hearing birds chirp, or feeling the warmth of the sun. Metaphors and similes can help you greatly here.
Steer away from abstract words like love, sorrow, indignation, friendship. They are vague compared to more concrete words and phrases, things that can be perceived by one or more of our senses.
A second reading of your poem, some days after writing, will give you surprising insights. Obvious now are things that need to be revised, and you may wonder at how different it seems from the vision you had. Repeat the process of rest and revision until you feel satisfied.
Then let others, more than one, read it: those who will give you truly honest opinions. You need a variety of opinions before you choose any option but your own inspiration.
– Ruth Strachan