One of the keys to good writing is to consistently choose strong verbs. Strong verbs are verbs that call up vivid mental images, that allow the reader to picture clearly what is being described. Sentences with weak verbs don't hold the reader's attention as well. For instance:
The fire was hot. It had many flames. The flames made the marshmallows black.
The verbs in these sentences are all weak – "was" "had" and "made" They are too general to conjure up much in the mind's eye. Now, consider this alternative.
The flames licked at the marshmallows, scorching and blackening them.
This new sentence still uses three verbs, but they are much stronger – "licked," scorching" and "blackening." The first conveys a clear sense of the flames movement, while the last two vividly demonstrate their effect.
This leads to the question of how, exactly, one comes up with strong verbs. Several methods exist. The most obvious is to scan the original sentences for nouns or adjectives that can be turned into verbs. This is the case with "black," for instance, in the example above. Another is to think of standard verbs associated with the main noun. In the case of "fire," the verb "burn" comes to mind fairly quickly. Then look up that verb in a thesaurus. This will give you a long list of potentially useful verbs that you might be able to use, including "scorch." Finally, you can think of ways you may have heard other people describe whatever it is you are describing. For instance, the verb "lick" is used in conjunction with "flames" fairly frequently, as in this news story: independent.co.uk/news/world/australasia/sydney-shrouded-in- smoke-as-bush-fires-drive-60ft-flames-into-suburbs-668080.ht ml
Bear in mind also that English differs from other languages in having many, many more words. This means that there is almost always a more specific verb that can be used in place of the generic one that first springs to mind. So, for example, in English you can run. In many languages, that would be it. If you wanted to spice up the sentence, you'd have to do it by adding adverbs, as in "he ran quickly," he ran slowly," and so on. In English, though, you can employ other verbs, instead. You can say a person sprinted, jogged, loped, dashed, scampered, scuttled, or engaged in any one of a dozen other types of running. Be careful, though. Each of these words might come up in a thesaurus if you looked up the word "run," but they are not all pure synonyms. There is a great deal of difference between the speed of someone who is sprinting and the speed of someone who is loping, and a crab is far more likely to scuttle than to scamper.
Verbs that are less common tend to be stronger, even if there isn't a particularly vivid image associated with them. So,
I took a course in physics.
isn't as good as
I enrolled in a physics course.
The reason for this is that we are so used to certain very common verbs that our minds glide over them. Also, "enrolled" may not conjure up a particularly strong mental image, but it is still more specific that "took," and the specific is always more interesting than the general.
If you want to improve your writing quickly, start by going through the first draft of anything you write, go through it, and highlight all the verbs, then try to eliminate all of the weak ones - "to be," "to have," "to do," "to go," to take," and "to make," are particularly common offenders. It may be difficult to think of replacements, but in most cases you can solve the problem with a bit of ingenuity and a lot of tenacity.