Native speakers of any language know naturally which words belong together. They have heard their own language so often and in so many situations that they can naturally put words together in a way that sounds effective. The foreign learner cannot do this.
Unfortunately most language schools teach vocabulary and grammar. Vocabulary is very important. You need words, not only the high frequency words, but also the less frequent words, in order to be able to deal with many situations. But research has shown that you cannot learn them from lists or in groups. You cannot learn by studying the terms for the parts of the body, or what to say at the train station, or the colours, or opposites or words that mean the same thing. This will only confuse you. You need to learn words in context.
The ideal context is the phrase. You can learn a phrase to go with each new word you learn. Soon you will have a variety of phrases with the new words you have learned. Each phrases gives the word a slightly different meaning. Each phrase is a proven way of using the new word in combination with other words.
Every sentence is unique, but phrases repeat themselves often. A phrase is any group of two or more, (usually no more than five) words that naturally belong together and can be used in many situations.
Learn to look for phrases, save them and learn them. One word of caution is necessary, however. The phrases must come from meaningful content that you are listening to and reading. Free examples of sentences and phrases from dictionaries are false friends. You think you are learning but you are not. You need to find your own phrases as you discover the language from interesting content. That is why at The Linguist we let you create your own database of phrases from the real life content that you find in our large library, or from other articles that you find on the Internet.