Typo in the title. Typos happen, but if you don’t check the spelling of your own title, it bodes ill for the rest. For that matter, a few typos in the body of the piece are no big deal. More than one per couple of pages says you’re not proofreading.
Poor opener. The opening sentence sets the tone for the rest of the story. Poor grammar, convoluted clauses, and typos are obvious no-nos. A sentence that doesn’t do anything to give us a flavor of the story won’t help much either.
Can’t follow rules. We’ll look at anything, but when we say we don’t really like military SF or zombies or racism, and we do like vegans, and you send a story about a racist zombie army that eats pigeons…
No story. We want stories with beginning, middle, and end, with forward movement, character development, and impact. We’re not looking for moment-in-time scenes where little is resolved.
‘Was’ instead of ‘had been’. Learn how to use the past perfect continuous. No, we don’t care what it’s called either; we had to look it up. There are times for ‘was’ and times for ‘had been’. They’re different. We see a widespread inability (reluctance?) to use ‘had been’ properly. It may be the most common grammar flaw we see.