To strengthen the sentence, you need to use verbs. You are writing in a verb-free style. The participles ("selecting", "enriching") come from verbs but they are adjectives, not verbs. Furthermore, it is difficult to discern what might be the nouns that these adjectives modify. What does "selecting" modify? "Lessons"? "Priority"? Likewise, it is impossible to figure out what noun is modified by "enriching". "Lessons"? "Strategies"? Even the infinitive ("to tailor") does not act as a verb. It is a noun. The only true verb in your sentence is "is" ("it is my priority"). Without verbs, the sentence cannot contain any action. Only verbs can create action. That is the reason you are confused about what enriches what. It is because in your sentence, nothing happens. No verbs - no action - nothing happens. To find useful verbs, look first at the true verbs that are hiding behind your participles ("select", "enrich") and infinitive ("tailor"). You do not need to turn all of them into verbs, but that is a good place to start searching for verbs: "I will tailor our lessons to fit your needs. We will select an effective strategy that enriches your vocabulary and enhances your expressivity." When you use verbs like this, it becomes very clear what is enriching what, and what is enhancing what.