Some things I keep seeing:

1. Failure to edit vigorously. This includes spelling and punctuation. I see a lot of poems that may have a really nice core, a diamond in the rough, but it’s surrounded and obscured by a lot of irrelevant fluff. Spelling, punctuation and grammar errors are distracting and disappointing to the reader. Serious writers almost never publish their first draft. Proof readers are helpful.
2. Excessive vagueness/word salad. Sometimes it seems that some would-be poets throw words together randomly to make others think they are profound. The great poems are pretty clear; you know what they’re talking about.
3. Failure to use poetic language (or use language poetically). If the poem’s line breaks are removed, does it read like a term paper? A poem should still sound like a poem regardless of the formatting. “Do not go gentle into that good night, Old age should burn and rave at close of day; Rage, rage against the dying of the light. …” – Dylan Thomas
4. Lack of organization. A poem delivers an image, a message and a feeling. The sequence of elements in a poem contributes to its ultimate impact. Elements that do not contribute to that ultimate impact dilute the effect and should be discarded. A poem should be only as long as it needs to be.
5. Too much personal information. You’ve seen them: “Yada, yada, yada… by the way, my boyfriend is a jerk…yada, yada, yada… I popped three zits this morning…” Most of our readers are not actually interested in the intimate details of our personal lives. You probably really don’t want to hear about the bladder infection I had last month. This is tricky because some personal information when used artfully can add to the richness of our work.
6. Missing the ending.  When a poem is working well, we have a tendency to try to keep it going. We write a 60 line poem that actually should end on line 30.  This seriously dilutes the impact of the poem. I see a lot of poems that simply go on too long. One symptom of missed ending is when a poem starts on one subject and ends on another.
7. Lack of imagery. It is better to “show” by using verbal imagery and action than to simply “tell” the reader what you are thinking. If you can make your reader see something you will reach them.
8. Excessive abstraction. Abstraction is necessary for logical thinking. Abstractions are words that are one step removed from concrete reality. “Round” is an abstraction. It is a property shared by millions of things in our world. “Basketball” is a concrete manifestation of the abstraction “round.” In the sentence “Truth and beauty are universal,” three of the four words are abstractions. The problem with abstractions is that they tend to be semantic blanks when used in a poem. They are empty of concrete reality.
9. Failure to find the music. The most successful poems are songs. We are not required to write rhyming poems with rigid meter, but even when we write in free verse, the poem retains an element of song. This is where reading the work aloud can really help. Listen to how the words sound and where they fall in the body of the poem.

Parting Thoughts

When I first began to do “creative writing” back oh-so-long ago, I had a sort of fetish about my own work, almost as if I thought of it as divinely inspired. Hubris, I know. I simply did not look at my own work with a critical eye and seldom rewrote anything. We were still using typewriters then and changes were a pain in the ass. I wasted a lot of time and energy with that attitude. I got over it, but it took a long time. The way I got over it was a long process of getting a bit of my work published, listening to the reactions of others to my work, and giving talks. I wrote a play that was performed by real human actors and I got to watch it. I learned that I preferred to find my own mistakes rather than let other people find them. Getting the reactions of other people to my work was vitally important in the development of my critical eye. “Likes” on a blog or social media post don’t count. Often my friends will give me a quick like because they like me. Likes don’t imply a deep engagement and human reaction to the piece. Have you ever read a poem (or other writing) out loud to another person? It’s helpful.

Hopefully these notes can save you some time.