If you don't have time to read, you don't have time to write.
Read as many books as you can in the genre you want to write.
But, how do you read in a way that helps you to write?
Here's just 3 ways -
Do you skim any text, or just go past it completely because it doesn't interest you?
If so, learn from it and don't write anything similar in your book, whether its long drawn out description or over flowery language.
Just as you can learn from what you don't like in a book you can learn from what you do like.
Does the author ensure all their characters stand out because they're so different? I love it when they do without dragging the story down to a snail's pace.
Think about what makes the main character stand out or be a cliche. In a crowded genre like crime thriller you have to do something different.
I've tried to make Detective Inspector Duncan Waddell in my Detective in a Coma series different by making him doubt his sanity because everyone tells him his friend and colleague Stevie Campbell is a coma, but he's talking to him. This not only gives Waddell something that will make him stand out, it also gives Vile City and the rest of the series a supernatural angle.