1. Use advanced vocabulary and grammar: Using some advanced vocabulary and grammar, such as professional terms, Latin or French, can make down-to-earth expressions sound more advanced.

2. The way of expression should be unique: avoid using too common expressions. You can use some literary and artistic expressions, such as metaphors, metaphors, symbols, etc., which can make the expression more down-to-earth. There is depth and artistry.

3. Quoting famous quotes: Quoting some famous quotes can make down-to-earth expressions more authoritative and credible, and can also enhance the sense of high-level expression.