Strategies for overcoming writer's block vary wildly from person to person, but there are tricks and suggestions to get your pen flowing. Imminent deadlines, distractions, and frustrations can interfere with your prolific output. Some people stick to a strict schedule; others prefer spontaneous outbursts of creativity. Find what works for you.
Many writers swear by quick exercises, called warm-ups or freewrites. They don't specifically have to do with the topic at hand, yet they excite those creative juices. Freewrites get you to observe things you don't practice noticing and prompt you to describe them in unusual ways. For example, you have eaten hundreds of apples, but have you really thought about what the experience of eating an apple is like? Describe its exact hue, twisting stem, and creamy texture. Write down your actual experience, rather than what you assume the experience should resemble.
Freewrite ideas are widely available on websites, but make your own list. It could be describing a time you got lost, what you (or your character) would do if you found a treasure map, or a convincing argument for believing in alien life. These short exercises might get incorporated into longer pieces later, but not necessarily.
A famous saying goes, "If you have nothing to say, you're just afraid to say it." If your writing seems irrelevant, boring, or hopeless, this can cause a spiritual kind of writer's block. Remember the moment you got your idea. There was a reason you cared enough to devote so much time to your poem, story, or article. Getting in touch with the purpose, moral, or inspiration for your work may encourage you to finish it with enthusiasm.
The pressure of desiring to complete a "perfect" piece can overwhelm the detailed task of writing. While you write, don't burden yourself with imaginary critics, negative reactions, or that voice of doubt. Overcome writer's block by staying in the moment, not leaping to a pessimistic future.
Sometimes the best way to overcome writer's block is simply to take a break. Do something you enjoy doing, such as taking a walk, playing with pets, baking cookies, listening to music, or calling a friend. This will not only take your mind off the "problem" of writing, but it might remind you that writing should be enjoyable. While you pursue these activities, you can wonder how they would or wouldn't figure into your story, as well.