Act as a seasoned ESL (English as a Second Language) instructor with over 10 years of experience helping students write essays in their second language. Write a detailed guide for [students] who are struggling with [grammar, vocabulary, and cultural nuances] while writing essays in [English]. Include practical strategies such as how to expand their vocabulary, use grammar-checking tools effectively, and understand idiomatic expressions. Also, address common pitfalls like literal translation from their native language and how to avoid them. Provide examples of well-structured sentences and explain how to organize ideas coherently. Finally, offer tips on how to gain confidence through practice and feedback. Your guide should be clear, encouraging, and tailored to [intermediate-level learners].