In its ideal form, it is applied uniformly and across-the-board on ALL imported goods, regardless of nation of origin, with absolutely no exemptions and no add-ons.
Revenue tariffs are also essentially self-capping.
At low rates, revenue will increase as the tariff rate is increased.
However, if the tariff rate is increased too much, revenues will begin to decline as trade excessively diminishes.
It is that "optimal" rate level that maximizes revenue that we should strive for. That will provide the best opportunity to decrease other forms of domestic taxation.