The default nudging effect describes the predictable altering of user behavior through positive reinforcement
When you create a default nudge you are suggesting, for instance, that the default option is the most commonly chosen one. This tends to make more of your customers choose this product and can include highlighting a product on your website as a "preferred option" or naming conventions like "standard product" vs. "plus product".
Avoid patronizing your customer by suggesting that they are not capable of making the right choice
Like any behavioral effect, its success is dependent upon your overall offer architecture incl. pricing and product composition
Nudging effects work better in situations in where customer do not fully know their needs
"Nudge: Improving Decisions about Health, Wealth, and Happines" Richard H. Thaler & Cass R. Sunstein