Don’t just write "flower". Write "frangipani". But be careful. When you're being specific, be accurate as well. "Scented frangipani" is fine, but be sure that you know whether a certain flower has a scent or not before you say that it does.
Many of your readers will be experts in the subjects you're writing about – so you should be accurate in your fiction as well. Every second romance novel I read has the hero and heroine galloping their horses madly hither and yon. This is nonsense. If you're writing about riding, know the paces of a horse: walk, trot, canter, gallop. No one gallops a horse without warming up its muscles, nor do you gallop over rough ground, unless you want to break your own neck, and the horse's, as well, nor do you gallop a horse on a casual hack through a park. Check! At the very least, if you're inaccurate, you'll annoy your readers and lose sales. At the worse, readers will write to your editor (and you) to complain that you're careless and incompetent.
Research is always vital. If you're writing a novel, and your character is a zoo keeper, go and interview some zoo keepers.
If you feel stuck in your writing, it may be that you don’t know enough to describe accurately. Read. Research. Free-write. Then go back to work on your writing.