How can I make my written language more sophisticated?

Using complex structures, for example things in the subjunctive mood - Il est important que je fasse mes devoirs chaque nuit... in place of je fais mes devoirs. Use a range of people, pronouns and tenses (don’t just stick to present!) Thing about indirect and direct object pronouns to avoid repetition of the noun - Jules adore Molly. Jules lui donne un cadeaux... instead of Jules adore Molly. Jules donne un cadeaux à Molly. A step further than this - Jules, qui a donné un cadeaux à Molly, l'adore. Always give opinions but have multiple sentences to introduce this, not just verbs CROIRE and PENSER, but also à mon avis, il me semble, de mon point de vue, selon moi, d'après moi... Use connector phrases, and again with a variety of them eg bien que, cependent, alors que, d'une part... d'autre part, en ce qui concern, en fin