There exist certain rules to respect in order to create a good sentence with coherence and cohesion which is grammatically correct. First of all, you have to provide your sentence with complexity, but you dont have to make them too complicated, You have to use all the elements (noun, adverbs, prepositions, verbs and adjectives) in order to create a sentence with subject and predicative in order to convey a complete thought with sense. Secondly, you have to organize the sentence propoerly by using correct word order.